The cover will include two Oklahoma State Quarters (one each from the Philadelphia and Denver Mints) from the first day of mintage. The card will have a 41 cent American Flag postage stamp with the postmark of January 28, 2008, the day Oklahoma Quarters were released.
The covers are priced at $14.95 and are limited to a production of 35,000. The Mint’s product page is available here.
These covers have not traditionally been strong sell sellers, but may present a longer term value. Earlier State Quarters had much higher production limits than the 2007 and 2008 State Quarter Coin Covers. In 1999, productions were set at 100,000, but declined steadily as the series moved on.
Also of interest, NGC has been encapsulating and grading these First Day Coin Covers. The entire cover is placed in a special holder with a separate grade for each coin. Full details and instructions for submission are here.