Hi daroz,
If U want to stay WITHIN the main areas in Paris, the cheapest hotels would be the IBIS chain which is about 85-95 EUROS (about US$120-130) per night excluding breakfast (7 -10 EUROS extra depending in location of IBIS)
All the IBIS rooms are very very basic, small (as with all Paris hotels) but clean.
If U can spend a bit more and want to stay a a really charming hotel, I recommend the Hotel des Grand Ecoles
http://www.hotel-grandes-ecoles.com/
It is about 135 EUROS per day and they book up very fast bcos it is really a great little hotel for Paris (Has own garden, quiet even in the centre of town)
If U want to save on the room, U can try the IBIS Suresnes which is a bit outside the city (about 40 minutes to get to Concorde/Charles de Gaulle Etoile Metro stations) and is much cheaper (39 EUROS per night if U book online in advance) It really is just about the cheapest clean place U can find in Paris.
To get there, take the Metro to La Defense and change to the Tramway and stop at Suresnes-Longchamp. Alternatively take the RER from Gare St Lazare directly to Suresnes Mt St Valerian.
Enjoy ur trip and try Angelina's (opp. Jardin Tulleries) if U love hot chocolate! One of my fave things about Paris!
