Tiger, don't believe everything you read on the internet. If you check out yachtworld.com you'll see those boats typically sell for $5000-$10,000 (asking prices) and there's usually an INBOARD ENGINE.
Apparently the CL poster neglected to mention, he's got no engine and that boat really is supposed to have an inboard. (Yes, you can bolt on anything, no, it probably won't ever sail right, that's a whole other discussion.) Price of installing an inboard engine? You guessed it, more than the price of buying a whole other boat that already has one. Without the soft spot on the deck, and whatever else the seller wasn't being honest about.
There are real bargains to be had out there, but if you're new to boats, and a boat is priced WAY below others, it is time to be very, very, careful. It isn't hard to sell a boat at or near market price--if there's nothing wrong.