Based on the Marvel Previews #12, July for September 2013, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Marvel Universe Ultimate Spider-Man #18
Scarlet Spider #22
Superior Foes Of Spider-Man #3
Superior Foes Of Spider-Man #3, variant Mark Bagley
Superior Spider-Man #17
Superior Spider-Man #17, variant Olivier Coipel
Superior Spider-Man #17, variant Spider-Man 2099
Superior Spider-Man #18
Superior Spider-Man Team-Up #3
Superior Spider-Man Team-Up #4
Ultimate Spider-Man #27
Guest Apps
Mighty Avengers #1
Mighty Avengers #1, blank variant
Mighty Avengers #1, lego variant Christopher Jones
Mighty Avengers #1, sketch lego variant Christopher Jones
Mighty Avengers #1, variant Bryan Hitch
Mighty Avengers #1, variant Skottie Young
Spin-Offs
Superior Carnage #3
Venom #40
Venom #41
Reprints
Marvel Universe Ultimate Spider-Man Vol. 4 Digest TPB
Spider-Man 2099 Vol. 2 TPB
Ultimate Comics Didived We Fall, United We Stand TPB