There's usually taxes & fees added on - they should be able to tell you when you sign it or before you do...

many websites will give the full cost of a room with all fees included so you can compare them easier.
- like priceline, travelocity, - there's lots more but I can't recall all the names

Doesn't hurt to ask about any specials, discounts or price breaks at the desk or call ahead and ask.
They don't make any money if a room is empty
So if a lot of rooms are empty you have a better chance of getting a discount.