I have used Priceline "Name your Own Price" three times. Twice I got the Hyatt for under $50 per night (without taxes and fees). The other time I got the Marriott which does have a shuttle. I think I got that for about $50 as well.
I just checked biddingfortravel.com and there are posts where the Hyatt has gone for $40 a night.
Most of the wins that I have seen are for the Hyatt or the Sheraton. I agree with the PP that you save so much over the rack rate, the cost of a taxi would easily be doable. You can check the approximate fare at mearstransportation.com