Craigslist can be great.

Lots of nice barely used/underused bikes out there for half the cost of new & less.

I've purchased at least seven bikes through CL- no problems.

Look for private party sellers whose story makes sense. Pass over situations that seem off to avoid scams, stolen bikes, & (pardon the term) weirdos.

Not a bad way to try out a few bikes, if you don't travel too far.