When performing a DeFi Swap on one of your wallets connected to CoinStats (e.g. Metamask), you'll pay a small transaction fee of 0.875%, which is automatically factored into each swap. This is used to support ongoing CoinStats development.
You are also going to pay the Network Transaction (gas) fee. This one refers to the fee required to successfully conduct a transaction on Blockchain. In essence, gas fees are paid in the network's native currency, i.e. Ethereum for Ethereum network.