If you're really going to do this, ask yourself a question. The same question that a friend of mine, author James L Nelson (buy his books!), asked me, when I was considering it. "Do you like standing in a cold shower peeling off $100 bills??? Then you'll LOVE sailing!"
First piece of advice; Don't look for TOO much of a challenge. You'll work forever, spend WAY too much money, then give it up in disgust. Some other guy will benefit from your hard work and money. There are a million boats in the $5000 or less range out there. A coat of paint, grease a couple of fittings and you're on the water. I just saw my boat (a Lancer 25) for sale, on a trailer, for $1450. The guy was sailing it last year.
If you haven't bought yet, I'd suggest a 22-25 trailerable. You get a good cost-to-sailing ratio and location flexibility that you won't find in the big girls. My Lancer 25 is moored in my drive way. Some marinas offer lot storage for trailerables too. Otherwise, a slip might cost $2500/year plus hauling and storage. Moorings are cheaper but still cost some.
Paint is a world of its own. Depending on the boat, use and storage, you can pay $60/gallon to $300/gallon. If you trailer and are in fresh water, VC-17M ($50/qt) or EasyPoxy ($110/gal - limited submersion) would probably be your best bets. If you're mooring, do some research before you buy, and ask the local guys what they use. Zincs are easy to replace and come in a zillion shapes.
I'd suggest picking up a couple of books by Don Casey. Don is the guru of sailboat repair, refit and rehab. Everything you need to know, he's written down and in easy, laymen's term. Amazon.com for about $10.