BuyDig offers the refurbished Vivitek Qumi Q2 720p 3D-Ready Pocket DLP Projector, model no. Q2LITEB, for $279. Coupon code "EDU50" cuts the price to $229. With free shipping, that's the lowest total price we could find by $166 for a new model. Features include 720p resolution, 300 lumens of output, and up to 30,000 hours of operation.

A 1-year warranty applies, but it's unclear who backs it.