Survey, plus
Of course, you have to get a survey. Don't overlook things like electronics, bimini, dodger, barbecue, etc; don't forget to make sure the stove and burners work; don't forget to flush the head a few times. These things are small but annoying as hell; even the little costs like a new VHF detracts from buying things you really want, like ... I don't know, curtains.Also, insist on speaking to the current owner. But don't talk ... just listen. If you listen carefully, you'll find that he'll tell you most of the points on the boat that need attention, mostly by offhand remarks. "Oh, that through-hull has always leaked, I just always sail on a starboard tack and don't worry about it and..." Also, you must must MUST take the boat for a test sail. IF you don't, there's no way to know the condition of sails, running rigging, etc.Keep careful notes and make sure EVERYTHING is noted down. This then has to be cost-estimated and deducted from the price.By the way: you will do best if you aren't in love with the boat. That way, you'll bargain hard and if you lose it, it's no big deal. The C30 is a wonderful boat--I love mine--but there are millions of them around for sale.