I picked up a Sigma 28-80mm F3.5-5.6 ii Mini Zoom Macro Aspherical Lens at an estate sale for next to nothing.
On the box it says "For Canon AF (including ELAN 7, EOS 30, EOS 7)
It fit fine on my Canon T4i and actually took a few decent macro shots.
The caveat is that the autofocus does not work. Is that because of the incompatibility of the lens with the camera or because the motor is stripped or broken?
EOS is the key word here. Any EOS lens will fit and work with any EOS camera. That is, if it is a Canon lens. With third party lenses it is sometimes difficult to tell if it works as it should or it is faulty. A few don't but most do work just fine. At any rate you paid pretty much what that lens is worth, "next to nothing."