If you pick a star level for a particular area will your match (if accepted) come from the hotels shown on the website, or can it come from a hotel not listed with same star rating?
It can come from another hotel not listed. They list the hotels as "examples" of that category, but anything in the area with a star rating at the level you select which participates can be pulled to meet your "bid."
Hope that helps. We've generally been happy with our priceline bookings, but we tend to stick with 4* options.
Go to betterbidding.com, they are a great resource to find historical trends in pricing/bidding and places people have secured based on cities and areas selected. They also will give you tips on areas within cities to select to get additional price matches if your first price is denied.