From The Comic Speculator:
(Excellent blog BTW)
Avenging Spider-Man #15.1, $2.99. WARNING!!! READ ASM #700 FIRST! Otherwise you’re going to spoil the ending. Turns out this issue is not the flashback story it was solicited as but it’s a prologue to Superior Spider-Man #1. I’m actually betting this issue is the hard one to find. It sold out as soon as retailers figured out what it was and there’s no second printing coming until January 30. Watch for this to go fast and it’ll be selling for at least $10 in no time.