An Iron Man story served as backup in #32, after which Marvel Tales became a standard-priced series reprinting a single Spider-Man story each issue, very occasionally with a new or reprinted backup story featuring anyone from the Inhumans to Spider-Ham.
Issue #32 featured an Iron Man story as a backup, and then Marvel Tales transitioned into a regular series where each issue contained a single Spider-Man tale, sometimes including new or previously published stories featuring characters like the Inhumans or Spider-Ham.