We're also on somewhat of a budget and want to keep our casino spending to about $100 each per day (4 day trip). We are probably only planning on actually gambling not more than 2 or 3 hours a day tops.
For my first ever trip to Vegas next month my wife and I are trying to see and do as much as possible, including visiting as many casinos as possible just to get a taste of them all (staying at TI).