Jesse Gan has written up a post on how you can get to EVO 2009, on Shoryuken.com.Assume you have 8 people in one room; the total per person comes out to about $60 for 3 nights.
The Red Rock is a 4 star resort and 8 people in one room is not a bad way to sleep. The room comes with 2 Queen Sized beds and plenty of floor space. 4-6 on the beds and 2-4 on the floor is easy.
Make sure you bring sleeping bags and extra pillows. It is very easy to find 8 people to fill up a room if you plan ahead.