Help with trading bot.

I use the three comma trading bot. I need advice. What is the best choice for exchange rate while living in the us and using three commas trading bot? Anyone use this method. Im looking for an exchange that is compatible and cheap exchange rates..? Thanks for the help. I use coinbase and its not worth it with the exchange rates but there must be another exchange i can use this method with that is also currently legal in the us. There must be a protocol for using this bot that can allow decent returns.?