I agree.. a $500 boat to learn on is great.. as long as someone can assure you that there is nothing terribly wrong with it. go to the marina and find a random sailor, offer him a couple of beers for his advice.. you can't expect a bulletproof bluewater cruiser for $500, but you should make sure nothing's about to "let go" on your first sail..
SO, that's my advice, find any sailor smarter than you, offer 'em a couple of beers and see what they say.. I'm not an expert, but if I'm the best you can find, I'd throw in my 2cents..
best way to find out if the bottom is easily cleaned.. bring trunks and the brush from the kitchen sink