Most projectors run 2000-3000 hrs..so it depends how many hours a week you run it. I had the my old X1 for 10 months and only ran it 300 hrs.
In your price range you have the Infocus X1, Benq6100 and the Optoma H30. Don't for forget to make sure they projector is relatively quiet. Infocus is notoriuos in having great quality pictured projectors but the fans they install are fairly loud.
What you want to look for is a projector with high contrast ratio. That will give you the best picture quality. For your price range you will only afford a 800x600 projector. The link posted above by other users are the best places to get info. Here is another.
http://www.projectorcentral.com/projector-reviews.cfm
Check my links below my sig for my projector shots.
