I found this one site that gives you cash back for purchases made on ebay and tons of other online retailers. What you do is click on the ebay link that is in your account (or whatever store you want to shop at)and then bid or shop on that store like normal. Then, when you finish making the purchase, about a week later, you get cash back in your account at the site. At the end of each month they pay you with paypal. So, there's no risk of credit card fraud or anything.
There honestly is no catch. I've recieved the money from them. This is how it works:
You buy something on ebay --> Seller recieves your money --> ebay charges seller a fee --> Big Crumbs (the site in question) recieves a commision based on a percentage of the ebay item --> Big Crumbs pays you a percentage of what they get.