"Uncommon" sounds about right. I have had 3 copies of this and find a copy with about every 10 to 15
FR box sets. TSR printed a lot of
FR campaign setting box sets. The Acaeum lists only 2 different prints with the original cover but I'm sure I have had 4 or 5 or more different prints. They seem to pile up on me sometimes. Not sure why some poster on your thread suggested the send away cards were rare, I'm sure TSR must have printed 100,000+ copies of the
FR core set with the cards. Most sets I find have the cards, it takes effort to through them out so most people just left them in the box along with the other advertising pages. 2 of the 3 copies of SoS I have found were in the
FR campaign setting box too, the 3rd was in a lot which also contained his set. Similar to the Jade Hare, those that ordered away for it, kept it with the set that originally had the card.
Congrats on the auction, that is a great price - more than double what I would have guessed.