The important thing is to do your research. I have done Priceline and Hotwire for the last year and half and saved a ton of money. I usually book 4* hotels, but sometimes 2 1/2's are fine. BetterBidding.com deals with PL and HW both. Their hotel lists, especially for HW, even though not totally complete, can help narrow the choices down. Biddingfortravel.com deals with PL only. Just reading through the posts for the area you are looking at should give enough information to bid effectively. You can ask for assistance, I never have, but most people should be able to figure out where to start bidding by reading the posts.
For our upcoming trips I used PL...San Francisco, 4* Le Meridien, $88 bid accepted....webrate $304. Portland, OR, 4* Westin, $75 bid accepted...webrate $164. Phoenix, 2 1/2* Courtyard Camelback, $46 bid accepted...webrate $139, and this one was an overbid.
Used Hotwire once to get the Omni in San Francisco...knew from research which hotel it would be so went for it and got it. Also bid $75 once and got the same Omni.
A little research equals big $$$$$ savings.
Good luck.