This is taken from the Swagbucks website:
Swagbucks is a search engine that offers you the chance to win cool prizes from swagbucks.com every time you search
OK, so how is this eBay related. Easy. Once you earn enough swagbucks you can redeem them for prizes like Amazon and Starbucks gift cards. Gift cards typically hold their value on eBay. So go ahead and list them and earn some cash. It's that easy.
Plus if you install the Swagbucks toolbar you can win without even using Swagbucks. You have a chance whenever you use the Internet, just make sure you stay logged into Swagbucks.