The central goal of foam core mounting is to create the impression that the print is part of the foam core board, necessitating careful mounting procedures with a significant margin of error.
The board has a foam center sandwiched between two identically cut sheets of paper. Lightweight yet sturdy, foam core can come in a variety of sizes and colors, and is typically intended for short-term use.
Some styles of foam core are designed to be more durable. Another line of foam core has an adhesive back, significantly simplifying the foam core mount.
The method for mounting onto the foam core could be as complex as a full-on mounting (necessitating measurement tools, Exact-O knives and painted solid backgrounds) to simply buying Velcro-like adhesive supplies.
Labs, galleries, art and craft stores may be able to perform foam core mounting for a small price.