Well indeed budget is the matter, with that one can achieve the results accordingly like you have suggested the cheaper of cheapest options toward screen, that way one can get projectors for 30,000/- rupees, and can use plastic chairs instead of proper seating etc.
By going for cheaper or cheapest solutions it is not good in any way during long run so i think it is better to have enough monies and better taste for giving due respect to watch a movie via projector.
V.