I shared about DYDX exchange before. It's a decentralized exchange. You pay gas fees only to deposit and withdraw. The usual trade TXs happen on L2. You pay small fees, but at the end you get rewarded with $DYDX token. The snap from the official site (https://trade.dydx.exchange/rewards) explains how it works. And the token value is fluctuating btw the $1.2 and $2.5 range since June this year.