Not much budget to work with there. Your best bet is probably to look at your local Craigslist, and beware of something that looks too good to be true. Be patient for a good deal if you live in a fairly major metro area.
Other than that, there is a 3M refurb unit on the new egg site at the top end of your price range. Good luck.
Craig's list, and it takes time. Read here and at www.projectorcentral.com and learn what all the specs mean. When you see a projector posted google the model number and you will most likely see a link to projecotrcenrals spec page. Lean what new items coast and what you get for your money. This is important since people sell business projectors on craigs list as HT projectors (they are clueless as to what they are selling) and they want a 2-3 time more than they are really worth. You must know what you are buying vrs what you can get new and the cost. Lots of work, but you would/should know all this before you would spend $2500 on a new projector. How large a picture do you want, a used rear projection set may be a better value if you have no audio components for the projector. Just some food for thought..
I highly recommend getting a used Optoma HD70 (or HD32--it's the big-box store clone of the HD70). It has a great all-around 720p HD image and usually sells for under $400. Go for a projector that does a minimum of 720p native format DLP, with a contrast ratio of 2000:1 or better.
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