No need to keep up with the bottom paint. Just sail it regularly and do touch ups now and then. Dive & scrape. Yes you can get 10 years from a good bottom job...
Seaworthy boat for that price? Yes. Contessa 26 comes to mind. Rawson 30's of course. Older Columbias, Cal's, Pearsons etc...
$200/month... you wish. There isn't really a 'monthly' cost. Just really big ticket items you should either plan on or budget for.
A new bottom every 5-10 years will cost you $4k on a 30 footer.
New engine every 1000-5000 engine hrs. About $12K.
New rigging every 5-15 years: $4K.
new Sails every 5-20 Years: 4K.
New running rigging 2-5 years: 1K
Batteries every 2 years: 1K
These are the biggies, and estimates quite on the high side. Always plan on the simplest things costing at least twice, perhaps up to 10 times their actual cost. Running a single bilge pump wire this spring ended up in a complete rewiring of my entire boat. In other works a $10 job ended up costing around $400. Of course you can bargain hunt and dumpster dive, but a "new" set of used sails will still cost you 25% of an actual new set but you will have to replace them 4-5 times as often and you will be less satisfied... You can get a used or rebuilt engine but it is still going to cost thousands... etc etc... Just my take.
Conceivably you could buy a boat for $10K, put about $5K in upgrades, shove off for a few years and spend little to nothing on maintenance. Then dump it when you are finished and you are out nothing. Plenty of people sailing about using that method.
Edit: I have some videos that show you what a Rawson would be like to sail, click here.
You can get these boats, or similar older boats, in the price range you are looking for that will take you anywhere you want to go. With the economy sucking so bad you can get really good deals.