Its something I've thought about often and is less difficult than you might think.
The hardest part is finding the right spouse, and that's whats held me back.
Anyone can buy a boat, and on a budget they aren't even as expensive as a new car. Its a matter of research and careful choice. Here's a steel-hulled 'down-wind' (slow as f*ck) boat for $29K:http://www.yachtworld.com/boats/1981/Tayana--2753403/Fernandina-Beach/FL/United-States#.VgMESstVhHw
Now you just have to learn to sail her, read the weather and become a navigator. Your time in port will cost you, but on the hook its free, and you can eat fresh fish for free forever.