In the entry level, minimal investment group, I think the best buys are Alberg 22 s, fiberglass folkboats and old Contessa s. They are all pretty well bulletproof and have that salty yar look. The Contessa has had a wide variety of engines installed through the years. Not much problem with blisters, but wet decks prove to be a nuisance. Engines vary from Graymarine to Atomic 4 s to repowered modern diesels.
Price is commensurate with power plant and year of sail inventory.
Corvettes and Albergs were good racing boats in their day and still have strong owner associations. Try and locate a spokesperson for the Association and get some good insights into what may be on the market. The next size range is dominated rightly, by the Alberg 37. In Canada this model is recognized as the queen of the full keel fleet and still sells at a premium price. The Bayfield line is characterized by beamy, shallow draft designs, well constructed with innovative interiors.