Here is the deal (my parents and sister lived in vegas for quite some time). First, go to travelworm.com and see who has deals on the days you want to go. If there is a big convention in town, the hotels cost more.
Second, you are going at the cheapest time of the week. You can stay at the rio for a decent rate and it is a nice room. Tropicana and Excalibur are great alternatives if you are on a budget. Both have clean rooms but are cheesy, the great thing is they are literally next to some of the big players.
If you have a car, stay at a station casino, boulder station etc... Again, cheap, $5 buffets, $29 rooms. Or stay downtown at 4 queens or fitzgeralds (very ghetto) and ride the bus $1 (ghetto, ghetto, ghetto). Stratosphere has good rates and admission to the tower is free for guests.
you can do vegas on a budget, but be aware. If you aren't gambling the booze is a bit pricey. If you do have a ride you can hit my ex-stepdad's bar...Don't Ask...on spring mountain.