I have used Price line on many occasions. I recently found the same price advertised on the hotels marque was that that I received through price line. That made me begin to wonder.
I recently made a trip that involved several hotel stays.Price line's prices were the same as the hotels "best rate" prices (I found you can get better with a AAA offer).
They don't seem to offer any discounts unless it is the "name your own price" feature. To this they add fees and often, the room that is reserved is one that no one would like.(Santa Fe, Inn of the Governors, great price, view of the garage)