It's really not as hard as it sounds: Buy a boat and learn as you go. Holland is great for boats if you're in Europe - I found mine on http://www.botentekoop.nl and paid someone to help me sail it to Copenhagen where I live. The trip across the Netherlands, Germany and Denmark helped me get acquainted with how a boat handles, what you have to be aware of, navigation, signalling, etc.
When I got to Copenhagen I started disassembling a lot of the insides. A lot of boats seem to have an emphasis on having as many bunks as possible so that ten people can sail somewhere or whatever. This isn't really what you want when you're living on it though, so I tore down some bunks and built a proper toilet, kitchen, dining area and office instead.
I got a place at a nice harbour and found that the people there were really nice and had a lot of knowledge of what to do whenever I had a problem. Don't go for an upscale place, they are snobbish and aren't very helpful. I found a harbour with half pleasure yachts and half fishing boats, the fishermen know everything there is to know about boats, and they'll gladly help. Spare anchors, hydraulics, and fishing nets lying around is a good sign.
There is, of course some maintenance depending on what you buy. You can buy steel, fibreglass or wooden ships. Fibreglass is the easiest to maintain. Steel corrodes and gets rusty so it has to be painted every now and then, but not really a big deal. I wouldn't recommend a wooden ship - it's lots and lots of work and it deteriorates quickly if you don't keep it up to standards with oil, lacquer, polishing ans what have you. Every three years or so you have to get the ship on land and bottom-paint it. It'll take a weekend and cost around $1000.
I pay $1200 a year for the harbour where I'm living, and paid $30.000 for the boat. I spent $10.000 refurbishing and redoing it.
I'm planning on going to Berlin this fall, it's only a few days sailing :-)
feel free to e-mail me if you want to know more, my mail is in my profile.