As for that unused treadmill, set of weights or soccer equipment you've never used ... If you have athletic and fitness equipment collecting dust in the garage, turn it into cash at secondhand sports stores, like Play It Again Sports. Bring your gear to the store, where a sales associate will review the items based on condition, brand and the store's current stock levels. The associate will determine the value of your items and either pay you on the spot or apply the value toward a trade. You can walk out of the store with new gear, money in your pocket or both!