Keep in mind that clients who pay low rates are not necessarily the best clients to work with, or ones you'd want to work for in the long run.
With that said, there are some niche freelance marketplaces you can consider using, but whether or not you can be a freelancer on those types of platforms depend on your skills as a developer. If your ability is not there yet, I'd recommend on working on that first to help build out your portfolio.
