limit vs market orders?

Im working on a bot to algorithmically trade crypto pretty fast, a few times per minute, and im also looking for a good exchange that has low fees since any commission fees would probably eat up any profit i make per trade.

when i was researching coinbases fee structure, i came across a reddit post asking about coinbases additional spread, and many of the comments were saying to use limit orders instead of market orders to essentially bypass that spread. is this true? how does that work?

and if it is true, is that just a coinbase thing or will that work on other exchanges which charge a spread but no commission?