34' Seafarer(1974): Condition (according to the ad, I haven't seen the boat yet) glazed gel-coating and some cracks in the fairing compound of the rudder... Needs new bottom paint... Looking at around 1-1.5K repairs?(I'm going to offer 9K if it looks good...)
27' Hunter(1978): Older sails (over 10yrs) ... Looking at 1-2K for new pair of sails?(I'm going to offer 7.5K if it looks good...)
30' Pearson(1973): Gas engine... The boat seems to be in OK shape. (Im going to offer 7K if it looks good...)
30' Cat (1976): needs new engine or rebuild... Rebuild the engine for 3-4K?(I'd offer 4K if I like it...)
My two cents...
The 34 is going to cost a fair buck to keep going. The others will be cheaper.
Gear for the 34 is one size up from a 30 footer in a lot of cases, and you're going to pay more for mooring, storage, etc., etc. If you're on a budget, it's going to be hard to maintain her.
Don't buy the Catalina - if the engine's pooched it can easily run you 10K to remove, repair, replace, reinstall, realign, etc. etc.
Personally, I wouldn't take a late seventies Hunter, regardless of how inexpensive it was...
The Pearson is a good boat.