OK......most model car kits come either in injected plastic. These are the more common kits from brands like Revell, Monogram and Tamiya. Resin is more of a low volume kit made from a mold that has a liquid, resin poured into it. Resin typically has less detail but is more expensive due to the labor and low production run. Die Cast is molded in metal and sold at a variety of stores. These are pre assembled models that can be nothing more than a pretty toy that may be equally at home on a book shelf to works of art. Of course, typically as quality goes up so does price. There are some $200 die cast that truly look like the real car but only smaller with little if any compromise due to the size of the model.
I know both kits fairly well.......REVELL by a ton. In almost every way, the Revell Camaro far exceeds the AMT kit. The AMT kit has its origins in the early 70's if not modified from an annual. The Revell is a mid 90's mold.