Go here:
http://www.vegastripping.com/vegasdeals/
You can get some great deals and may not have to compromise much on quality. Unless you like downtown (Freemont Street), I wouldn't stay off the strip.
Excal, NYNY, Luxor are a few decent places where you can get cheaper prices.
I've only ever stayed at MGM Grand and Mandalay Bay. You can get good deals at MGM Grand, we once payed $65/night, though that was through rewards offered through the players club.