I use Travelocity to compare prices. I just got one for the convention and the additional fees added up to 60% of the base cost. Once you know the cheapest you could use Priceline like suggested but just make sure that your plans are cast in stone since you pay immediately and there is no refund. I was going to use Priceline but realized that the total difference was only $18 and the conventions is still a long ways away. Not worth the risk.