COMC, also known as Check Out My Cards - is an online marketplace for trading cards and collectibles. Founded in 2007 by Tim Getsch, COMC provides a platform for users to buy, sell, and trade sports cards and non-sports cards, as well as other collectible memorabilia and items.

The concept behind COMC is to offer a centralised marketplace where collectors and sellers can easily list and browse a vast selection of cards and related material. One of the unique features of COMC is its consignment service, where users can send their cards to COMC to be listed for sale on their behalf. This service is popular among collectors who want to be able to sell their cards without having to go through the hassle of listing and shipping them individually themselves. Instead, sellers can send their physical cards to COMC's processing centre, where they are scanned, catalogued, and made available for sale on the website. 

Buyers can browse through COMC's extensive inventory, which includes cards from various sports leagues, entertainment franchises, and other collectible criteria - offering a wide range of options from vintage cards to modern releases, as well as both graded and ungraded cards.

Overall, COMC has become a popular destination for collectors and enthusiasts looking to buy, sell, and trade trading cards and collectibles in a convenient and secure online environment.