Here's my experience for what it's worth:
I've purchased tickets through priceline several times - they have never given me the price until after my bid was accepted. I'm with klc on this one, if you're getting a price quote w/o purchasing, it's not priceline. (I've seen ads for a priceline option where they quote prices in advance, but that's not "name your price" and I've never used that service so don't know how it works.)
Priceline works great if you are not in a hurry and don't care what airline. I tried it for the first trip to BZE from LAX but they would not take any of my bids up to w/in $100 of Travelocity's posted price. For the difference I'd rather be in control. Then ended up on TACA for less than my highest priceline bid so was glad they didn't take it. Also, if you're going to up your bids they usually make you change dates or airports or something, they won't just let you keep bidding up bit by bit.