If you sign up for skyauction, you can search the winners to find out how much resorts you are interested are going for. You can get incredible deals on last minute ones, if you're the patient type. "Ready Set Go" auctions usually go for great prices too ($50 +fees) but availability is limited to non-exisitant for high travel seasons (usually more units open up at the last minute, 2-4 weeks before your dates, but not always) and if you travel off season it's a steal. So much depends on when you are going, the less popular your travel dates are, the better deals you can get. I've noticed more resorts charging extra fees this year for summer travel dates. You have to read carefully before you bid, but all the info is right there.
HTH