The value of first day covers can vary widely depending on demand. A first day cover without a cachet or complimentary art piece may be considered worthless to collectors. Unparalleled pieces sell for much more. In 1996, a unique issue in the United States sold for about $120,000.
Increase the value of your first day covers by using limited-release stamps on matching cover. An informative or complimentary cachet to the left of the stamp also increases value. Commercially available cachets, often printed instead of painted, are considered less valuable than those produced in limited quantities by well-known artists. To understand the potential worth of your collection, contact your local first day cover resource or stamp club.