There’s a somewhat odd “Spider-Man: Sinister Six” sale going on, so let’s walk through it. It’s about the old Spidey villain group and some of the individual members.
It starts out with overlapping books. For $4.99, you can get Spider-Man: Sinister Six, which is the original tale from Amazing Spider-Man Annual #1 and then the sequel arc in Amazing Spider-Man #334-9 (192 pages). Or for $9.99, you can get Amazing Spider-Man Epic Collection: Return of the Sinister Six, which collects Amazing Spider-Man #334-350 and the Spider-Man: Spirits of the Earth graphic novel by Charles Vess (504 pages).
There’s the truly odd selection of Marvel Knights Spider-Man Volume 3: The Last Stand. Why is it odd? While Mark Millar and Terry Dodson are a notable creative team, that’s volume 3 of a three-volume story and the first two volumes aren’t on sale.
If you like the Hobgoblin, there are a couple things worth mentioning: Spider-Man: Origin of the Hobgoblin features some of the early appearances from Amazing Spider-Man and Peter Parker. Spider-Man: Hobgoblin Lives finds Roger Stern returning to wrap up the mystery of the Hobgoblin in the mini-series of the same name and also contains a follow-up story from Peter Parker, but the Stern/Frenz mini is the real draw here.
There are a few more things on sale, so feel free to have a browse for yourself… but be aware that The Gauntlet storyline was 5 volumes and they’ve only got the first 3 on sale (nor is the Grim Hunt arc that it leads into). Like I said, it’s kind of an oddly constructed sale.