(NOTE: This post is an "evolution" of this one)

I'd like to try making a projector using this cheap 2.5" 640x480 LCD screen.

I would like to obtain something like a 50" image from a distance of about 3 meters (9.8 feet).

Could someone pass me a project I could follow, with the right optics to buy, distances, etc.? I have a very small budget, I would like to stay under $100.

I'd like to have a folded project, as compact as possible, to make the projector very very small, but also straight-through designs will be welcome.

I don't care very much at quality/colors/uniformity/etc., I "just" want a projected image on a big screen from my PC for as few bucks as possible. - it's for a particular application, not for looking movies, so image quality is not a requirement.