Wiktionary
covermount
n. A freebie, such as a compact disc, mounted on the cover of a magazine.
Wikipedia
Covermount
Covermount (sometimes written cover mount) is the name given to storage media (containing software and or audiovisual media) or other products (ranging from toys to flip-flops) packaged as part of a magazine or newspaper. The name comes from the method of packaging; the media or product is placed in a transparent plastic sleeve and mounted on the cover of the magazine with adhesive tape or glue.