One of the most difficult things for sellers to do is come up with the right asking price for their castles -- one that will net them the most money, without the house laboring on the market for far too long.

Real estate agents are often helpful when it comes to pricing. But while many work with their clients to set the "right" number, others suggest too high a price in hopes of securing the listing, only to later tell the sellers they aimed too high.

Other agents suggest too low a price in the hopes that the place will sell on its own merits without much of a marketing effort on their part. In other words, so they can nab a quick commission.

Owners are sometimes culpable, too: Thinking their homes are the best on the market, bar none, they delude themselves into believing their places will fetch top dollar. Or, whether housing prices in their neck of the woods are rising, falling or just plain stagnant, they believe their homes are worth more than they really are.

According to a study set for publication in the Journal of Housing Economics, for example, owners tend to overvalue their homes by an average of 8 percent. Those who bought during the 2004-2006 boom years overestimate their home's value by even more: as much as 12 percent.

Whether with their agents' help or on their own, the study said, "homeowners systematically overestimate the value of their homes."

But soon, sellers will have a new Web-based pricing tool at their disposal. The program won't tell you what price to ask, but it will project with uncanny accuracy whether your home's value will be rising, falling or remain unchanged.

Currently, you can use the static and dynamic maps developed by Weiss Residential Research in Natick, Massachusetts, to chart how values have changed in your neighborhood over the last 12 months, and what they are likely to do in the next 12 months.

Soon, says founder Allan Weiss, you'll be able to do the same for your specific house.

The maps work like this: Go to weissindex.com and type in your ZIP code. (Note: Due to local disclosure laws, data is currently unavailable for 12 U.S. states.) A map of that area will pop up on the screen with a color-coded dot representing every house. A green dot means the price for that house has been rising; a red dot means its price has been falling.

Now, run the cursor over the years at the bottom of the screen and you'll see a historical perspective. If you see all green for several years and then some red, it means there's potential for a downturn. But if you see all red for several years and then some green, a possible upturn is in the offing.

These mini-indices are based on repeat sales and show changing values 12 months into the future for 100 major metropolitan areas and some 6,000 ZIP codes.

But Weiss has recently increased the database to include nearly 100 million residential properties throughout the country, making it possible to create similar indices for each of those houses. Within a few months, he promises, you'll be able to do the same for specific houses by typing in addresses.

The maps will not only show what the value of that house has been for the past few years, but also what its worth is likely to be over the next 12 months -- not a specific price, but rather a trend line.

The Weiss Residential Index is free to use, and Weiss vows it will never be used as a lead-generation tool for agents or lenders. The site will instead be subsidized through his agreements with others portals.

The name Weiss may sound familiar. He was CEO of Case Shiller Weiss, and was instrumental in bringing the popular and widely quoted Case-Shiller housing barometer to market. Case-Shiller shows how house values have changed over the previous 12 months in 20 major markets and dozens of smaller ones.

But that rear-looking index was unable to predict the 2008 housing market crash that sent values plummeting. That's when Weiss said he "knew something was wrong."

"It didn't help people recognize the crash," he said. "And it didn't show that even during the worst of the crash, some homes declined less in value than others, and some even appreciated. Nor did it show that some neighborhoods experienced downturns sooner than others."

The index he helped create was useless, says Weiss, who sold his share of the Case Shiller Weiss business in 2002. "People don't own their entire market. They own one house, and everyone needs their own index."

So he set about building a new index -- one that not only looks backward, but also forward. And over the last five years, he and his staff have developed tools that could possibly forewarn of never-before-seen market movements.

"Weiss maps show waves of value changes moving across a geographic area like a weather event," he explains. "New trends can be discovered, new sub-markets defined, compared and ranked, and better decisions made."

The maps can be helpful for buyers as well as sellers. Say, for example, you are considering two similar $400,000 houses you like equally. But one's index is rising, the other's is declining, and the forecasts show each trend is likely to continue.

So which place are you going to pick? Armed with the information from the maps, the decision is relatively simple.

The wider the net you cast when searching for financing, the better. It only makes sense to look beyond your local bank or mortgage company, and one place you may not have thought about is your friendly neighborhood credit union.

Credit unions are no longer the tiny cooperatives they were a generation ago. Back then, an auto loan was about the best you could hope for from one of these petite financial institutions. After all, they had fairly tight membership rules and, therefore, very limited assets from which to lend.

Now they are much larger -- the military credit unions like Navy Federal and Pentagon Federal are multibillion-dollar institutions -- and much easier to join. And not only do they offer mortgages, but they also are beginning to tap the capital markets for extra money to lend.

Today's credit unions have grown to resemble the savings and loans of yesteryear (without the crisis). And just as the old "thrifts" specialized in home loans, many credit unions do so now. Their bread-and-butter is still car loans, but mortgages also are a big part of their portfolios.

For instance, Pentagon Federal Credit Union, based in Alexandria, Virginia, reported originating $1.7 billion in first and second mortgages during the first five months of 2015. Annualized, that would come to more than $4 billion of mortgages this year alone.

Fellow military-centric credit union Navy Federal is even bigger. Open to all Department of Defense personnel, the Vienna, Virginia-based institution specializes in mortgages as well. The biggest credit union in the world, Navy Fed says it made more than $1 billion in mortgages just in March.

Credit unions made more than 8 percent of all mortgages last year, according to data from Callahan and Associates in Washington, D.C. That's a huge jump in share from the days of your father's credit union.

And they held almost $300 billion in first mortgages as of March 31, according to their federal regulator, the National Credit Union Administration. They also held $72 billion in other real estate loans, mainly second mortgages or home equity loans.

All of these are big numbers. Better yet, membership requirements have been significantly loosened.

Take the Dearborn Federal Credit Union in Michigan, which began life as a co-op for employees and family members of Ford Motor Co. It was started by seven Ford engineers back in 1950. Each of the engineers supposedly forked over five bucks to capitalize the business.

Now, DFCU has 200,000 members and more than $3.5 billion in assets. And you no longer have to work for Ford to belong. The credit union says: "People who reside, work, worship or are enrolled in post-high-school educational facilities in the 68 counties of the lower peninsula of Michigan are eligible to join."

Even that field of membership is flexible. According to the website, "Everyone is welcome, so if you don't qualify under one of these options, please call to learn about other ways you may join."

With its historical connection to Ford, you'd think auto lending would be DFCU's specialty, and you'd be right. But it is a big mortgage lender, too. It had $1.1 billion in mortgage collection rights at the end of 2014 and reported that its mortgage applications doubled last year.

Got 10 bucks? South Metro Federal Credit Union in Prior Lake, Minnestota, associated with the Shakopee Mdewakanton Sioux community, is open to any tribal member and anyone related to a member. But if you don't belong to that group, don't worry: A $10 donation will get you admitted.

One sign that credit unions are getting serious about mortgage lending is they are starting to participate in secondary mortgage transactions in order to secure more money to lend. For the uninitiated: A primary transaction is when a financial institution makes you a mortgage. In a secondary transaction, your lender sells your note to another financial institution for cash, often selling the right to collect your payments, as well.

A typical secondary-market transaction would be your lender selling your loan to one of the government mortgage agencies like Fannie Mae, Freddie Mac or Ginnie Mae. That way, the lender doesn't have to wait 30 years to get its money back. And as soon as your lender gets the money for your loan, it can relend those funds to other borrowers.

One way to measure credit union activity in the secondary market is to look at who attends the Mortgage Bankers Association's annual secondary mortgage market conference. This year, a record 20 credit union executives attended.

And they showed a variety of approaches. Take the Alaska USA Federal Credit Union of Anchorage, which invests in mortgage-backed securities issued by Ginnie Mae. This year, it is projecting $1.1 billion in mortgages and holds the collection rights to $5 billion in home loans.

Self-Help Credit Union of Durham, North Carolina has used secondary marketing to fund mortgages for low- to moderate-income and minority borrowers in partnership with Fannie Mae and the Ford Foundation. Over the last 10 years, it has made $4 billion worth of home loans.

To paraphrase that famous pundit, former Illinois Sen. Everett Dirksen: A billion here, a billion there, and pretty soon it adds up to real mortgage money.

(Freelance writer Mark Fogarty contributed to this report.)

There's no question that Miami has become a true international city, maybe even more so than San Francisco and New York. After all, it offers it all -- culture, sports, fine dining, plenty of sunshine and the one thing those other cities don't have: moderate housing prices.

But the folks at ERA Real Estate, the global realty franchise, have identified five lesser-known spots around the country that are now being targeted by buyers from other countries.

"We are seeing an influx of international buyers in these off-the-radar markets," ERA's Frank Malpica said at last month's National Association of Real Estate Editors annual conference in Miami.

ERA's "hidden gems" include Amelia Island, Florida, which it calls a "coastal treasure" 30 miles from Jacksonville, and Nashville, Tennessee, a "big city in a small-town body" that's famous for its music but also boasts nearly 30 institutions of higher learning.

Also on the list are Kingsland, Georgia, on the Atlantic coast three miles from the Florida line; Lake Norman, North Carolina, a 34-mile-long man-made lake

15 miles from downtown Charlotte, and Kennewick, Washington, which is located in the heart of the state's wine country along the Columbia River and has 300 days of sunshine every year.

But back to Miami, where the local real estate board has working agreements with Realtor groups in 126 other countries.

According to Teresa King Kinney, CEO of the Miami Association of Realtors, most international buyers use their Miami residences as vacation homes. Others actually migrate to the United States, and still others use their places to establish U.S. residency so they can send their children to college in this country.

Then there are those who invest here now with the idea that they will exit their home countries sometime in the future, said Ronald Fieldstone, a partner in the Miami law office of Arnstein & Lehr who specializes in immigrant visas.

According to Kinney and Edgardo Defortuna of the Fortune International Group, a high-end real estate firm based in Miami, buyers from China are the most recent international buyers to find Miami.

In the past, Defortuna told the NAREE conference that Chinese buyers have tended to invest in Los Angeles, New York and even Chicago because those cities have large Chinese populations. But now they have discovered that Miami also is a world-class city.

Defortuna told the story of a recent Chinese buyer who was having trouble communicating with a sales agent, so the agent gave the man a list of the 24 units still available in the property. The man marked out four units and gave the list back to the agent.

The thrilled agent thought the man wanted those four units, but it turns out he wanted the 20 he didn't mark out. He wasn't interested in the other four because their unit numbers didn't square well with Chinese superstition.

Although the Chinese are buying here in greater numbers, according to Kinney of the Miami realty association, they still are only eighth in the pecking order of international buyers, with just a 2 percent market

share.

The Realtor association executive also reported that Miami's foreign buyers paid an average of $444,000 per purchase last year, compared to $245,000 statewide.

Foreigners don't believe in mortgages, either. More

than 80 percent in Miami are all-cash buyers versus just 31 percent nationally, she said.

But while million-dollar-and-up estates and condo apartments grab the headlines, they hide the fact that Miami and environs are still relatively inexpensive. The median sales price in the country's eighth-most populous and fourth-largest urban area is still just $282,000 for a single-family residence and $207,000 for a condominium apartment.

Nationally, meanwhile, the National Association of Realtors reported recently that for the first time, the Chinese have supplanted Canadians as the top international buyers in U.S. real estate.

Overall, five countries accounted for 51 percent of all foreign purchases in the one-year period between April 2014 and March 2015, with China and Canada in the lead, followed by Mexico, India and the United Kingdom, NAR said. But the Chinese spent more than twice as much as the Canadians ­- $28.6 billion versus $11.2 billion.

NAR estimated total international sales in America for the period at $104 billion, compared to $92.2 billion for the same period the year before. This 13 percent gain was realized even though the number of transactions was down by 10 percent.

"The amount of money spent ... means international purchasers in the U.S. have become an upscale group of buyers," NAR Chief Economist Lawrence Yun said in a statement.

While international buyers purchase property throughout the country, four states accounted for half of all international sales: Florida (21 percent), California (16 percent), Texas (8 percent) and Arizona (5 percent).