I checked out kayak.com and they found a low price, but they referred me to the airline's website.

I haven't bid on Priceline, but every time I've used Orbitz, Travelocity, etc., I've found the same fares on the airlines' sites, minus Orbitz, etc.,'s fee. So I always book with them. My experience has been that if you book with Orbitz, etc., and you run into a problem with your ticket--and especially hotel reservation--the airline or hotel tells you to go fly a kite. They don't like those sites.