When it comes to can coolers the most common material they are made from is scuba foam. Foam is a more economical material which in turn makes those can cooler cost less.
The neoprene can coolers are made from the same material that a wetsuit is made from. It is a more durable, more flexible, denser, better insulating product, but they are more expensive.
The quick and easy way to determine if a can cooler is neoprene or scuba foam is by the stitching. A foam can cooler is typically sewn with a straight stitch on the inside of the product and turned inside out where the stitching doesn't show. When the neoprene product is sewn, it is typically butt edge and sewn with a matching (or contrasting) thread color with a ZIG ZAG stitch on the outside of the product where the stitching is visible.