hi ALI,
basically, what you do is just name the price that you would want to pay for a 2 stars, 3, 4 or 5 stars hotel in the area that you've chosen. then fill in the credit card infor and priceline does a search for you to see if any of the hotel rating that you specified accepts that price. they'll let you know 15 min after you've submitted your request. keep in mind that you HAVE to take the offer. i dont think you can change the request once they've accepted your price.
i put down 90$ for a 4 stars hotel and got the omni hotel in downtown boston before. so i guess it worked.
also, you can go to hotwire.com, i think they have good deals on that too..hope that helps...
- sallyc!