There are cell phones available with built-in projector and you can connect them to your PC too. They cost just around 1/10th of the big projectors.
Here are some of them:
Intex IN 8810 V.SHOW – Mobile phone with . Cost- Rs.11,000.
Samsung Beam- around Rs.20,000
Spice Popkorn M9000- Rs. 6000
(source:Technology News India - Latest trends in Technology)