check
http://www.boattraderonline.com/
You can find new and used prices, but beware that some parts of the US have a much more competitive boat market. But you can get an idea of markup and resale value. Also consider that buying off-lake will save you some money buy make thing less convienent. Some lake marinas won't service boats bought from elsewhere. Pretty much all marinas treat customers better than non- customers.