Your right, do not get anything with additives, coloring, etc.
I know there are other types out there. the stuff I get is sugar, HFCS, and water. It is the consistency of clay. Hard when its gets cold, and a bit soft when its warm. But you can cut it.
I put mine right on the inner cover whole. (Just make sure there are no entry points to the fondant from the top of the hive)