You can also do a pretty good assessment using eBay sold listings, but ONLY sold listings, not offerings. You also should probably discount bikes by $100 and frames by $50 for shipping...if the shipping is not called out separately. But, even on eBay, you need to consider what oddjob said...some markets are hotter, time of year...and condition of bike, of course, which can be hard to determine via pictures...but...I have found that, with a bit of work, you can get pretty good ideas on pricing from the auctions.