It is the first appearance in print of an important American author. I've never seen it for sale before, but if it was in a catalog of Peter Stern, Ken Lopez or Between the Covers (three of America's finest dealers in modern first editions) it would probably be listed for more than $300 in good condition (this one is not- it's missing the back cover, though still quite scarce).
I also received in the mail two other items for which I paid twelve dollars each on a "buy it now"auction. One 1950's issue of Harper's, the other Atlantic, each containing the first printing of a poem by a highly regarded author/poetess who met with an untimely death. Both magazines are in great shape. I would value each at a minimum of $50.
Modern authors in magazines are fun to collect and, with a little homework, can be profitable as well (though, as I said many times, I collect magazines because I like them and not for monetary gain). There is no reference to go to for guidance.
There are many appearances of J.D. Salinger, Steven King, John Updike, Hunter Thompson and others that are generally off the radar screen to eBay sellers but not astute collectors. Enjoy!
Oh, I almost forgot! The two authors I referred to at the beginning of this post?
Truman Capote and Sylvia Plath.