Amazing Spider-Man #800 was the best-selling comic book of May 2018. And at a cover price of ten dollars, it had no real competition as the #1 comic book in terms of dollars invoiced.
The new Venom #1 was in second place.
https://www.newsarama.com/40388-may-...es-charts.html
The rest of the top ten...
3) DOOMSDAY CLOCK #5
4) AVENGERS #1
5) BLACK PANTHER #1
6) BATMAN #47
7) BATMAN #46
8) JUSTICE LEAGUE: NO JUSTICE #1
9) THE MAN OF STEEL #1[*]
10) THE WALKING DEAD #179 (MR)
I'm particularly impressed that the Venom #1 beat out the Avengers.