To create the illusion that a virtual object coexists with physical objects and its environment is always an important goal in the research of augmented reality. Though there are already many commercial products on the market, they are too expensive, too cumbersome or too hard to set up for an ordinary user. Our "AR for the masses" system is cheap to build, easy to set up, and it does not require the users to wear a head-mounted display (HMD). Its cost is low because the whole system consists of only two web cameras (for 3D tracking), a paper box (as the proxy object) and a projector which is getting cheaper. It is also easy to set up: we can move the whole system to a new location easily and finish the calibration within just a few minutes.