I've seen a few complaints recently about the fees imposed by swap protocols so here is a bit of a stream of consciousness exploring the topic featuring Defibox and Uniswap with Binance as a centralised contrast.
Sources:
https://defibox.io/
https://app.uniswap.org/#/swap
https://uniswap.org/blog/uni/
https://uniswap.org/docs/v2/advanced-topics/fees
https://www.binance.com/en/fee/schedule