Don't limit yourself to craigslist. In my area craigslist mostly just brings up way overpriced bikes that the seller is asking what they cost new. My D-I-L in Colorado did get a very excellent deal on Facebook market place a couple years ago.
Don't buy a bike that you can't afford to have turn out to be a bad purchase. That way, if for some reason it's not the bike for you, you can simply get another bike and find out if that other bike is the bike for you.
IMO... Best way to buy the right bike new or used is to have experience with a lot of bikes. So get started.