If you have reliable transportation, consider living in one of the smaller towns surrounding Corvallis. It is significantly cheaper, and you don't have to be surrounded by undergrads. I was able to get a nice, new 2 bed/2 bath apartment in Lebanon for $895 a month. It's a twenty minute drive, which some people in Corvallis seem to think is VERY long; where I'm from, it'd take twice that long just to get to the other side of town.
There are several other towns about as far away: Monmouth, Independence, Philomath (actually much closer), Tangent, and so on. Monmouth is another college town (Western Oregon University), so there are plenty of accommodations for students.
There are plenty of bars in Corvallis, one or two dance clubs, and 7 breweries.
