Community colleges or local state schools can be a great place to start when considering going back for a degree, professional training, etc. They tend to be largely affordable and usually close by as well. The downside of course is that scheduling can often be a hassle, dependent largely on whether you're planning on going back to school full time or working at it part-time with a job. I am assuming you're in the latter camp.
In my experience, I would avoid online courses or certificate/degree mills like the plague. They often cost a LOT more than you would expect and in most cases you're not getting what you paid for.