What is Swappa? Swappa is a user-to-user marketplace for buying and selling used tech.Swappa is different than eBay and Craigslist as we do not allow junk products. We also review and approve all listings before they can be bought. This is a security feature to help protect buyers and make Swappa the safest place to buy and sell used consumer tech online.Selling on Swappa is free. Buyers pay a small fee.