Modest but not romantic is the Holiday Inn Express Le Bourget, if their is no convention, rooms are available at USD 50-55.
It is 10-15 minutes away from CDG( no hotel shuttle ) and minutes to a shopping complex ( Carrefour ) Breakfast is always included and good.
There is a busstop right in front of the hotel which takes you to the Gare du Nord right in the city centre for 1.25 USD in about 60 Minutes.You can also leave earlier and use the Metro, after 25 minutes.

My other recommendation is the Hilton Orly Airport.Especially on weekends they have brilliant promotions, starting at around 60 USD , if you stay at least 3 nights, but not sure if the promos are available on your specific dates.