If you feel comfortable using Priceline you can get some great deals. Last November I got the the Pullman Hotel, the old Paris Hilton, for $135 USD per night for six nights. Even though it was a little outdated, the location was great and we were only sleeping there for 7-8hrs each day. We were also able to use the facilities at the Pullman in Versallies after a long day touring.
Look up some some of the sites that give you tips on how to bid on Priceline and you cant go wrong.
One more thing, buy a Paris Pass online. It will save you hundreds of dollars on admissions to museums and it comes with a train/bus pass.
Stay at the hotel right in front of Concorde Square where Marie Antoinette lost her head. It's a short distance walk to some major attractions. And please do not get a rental car and drive in Paris. Not because of horrible traffic and drivers but because no place to park.
Also beware of pickpockets.
depends on your interests / activity plans, but you can check out the details at http://www.parispass.com/?aid=25&gclid=COaw0KLxirMCFegWMgodIDAAaQ .I should add we are only going for the weekend, so a couple days, does it still make sense to get the Paris Pass, will I get my moneys worth or because fo the short duration am i better off paying as I go? I am sure I will go back to Paris at some point and spend more time, so if I miss some things now can do it then.