Q: Suggestions for a film projector?

I have an iMac (2011) and movies on it in various digital formats (which I can play on my iMac no trouble) and would like a hassle free setup for a digital film projector.

I am fed up of sitting on my chair and watching a film, I would like to watch it on my wall, nice and big, so for that I will need a projector.

I don't know where to start, I don't have much of a budget and would like something in the £150 price range, second hand I don't mind at all, I just want to watch films.

I don't care about 3D or even Blueray, I have films from all time periods and besides, a good film is a good film.

** it's just for indoor use, at night time, I only need it to project from 4-5m away **

Can anybody help please?

Thanks!