Definitely yes to get a boat. I love mine and can't believe I waited so long to get one. And it doesn't have to be a ton off money and work if you keep it simple. Especially as you say you're looking for a freshwater lake boat which will reduce wear and maintainence. The hull if it's solid is unlikely to give you any problems anyway. All the motor will need is winterizing at the end of each season which you can do in an afternoon. Until something on it breaks, that is. But then you deal with it.
Definite yes to buying used. Craig's List is as good a place as any to start looking, get a sense of what's available and what average asking prices are for different rigs. Like when buying a car, look for a seller who took good care of it. You can usually tell just by asking a few questions over the phone. If he's clueless, that's a bad sign. When making an appointment to check out a boat, tell the seller you'll want to try starting the engine cold (and then when you show up feel the block to make sure he didn't cheat and warm it up aforehand). Also if it's an older boat/motor, find out if the original fuel lines, gaskets, etc. have been replaced with newer ones that are impervious to ethanol. If not but you like the engine anyway, make replacing those things #1 on your to do list. And last, make sure the seller has all the legal stuff straight (title in his name, current registration, hin plate on boat etc.). Research before buying all the things your state requires to allow you to register a boat. Make sure the seller can provide it or walk from the deal.
A great web site for boaters is thehulltruth.com. A great place to research, learn, and ask questions. Just avoid the user named Bushy. He's a doosh.