The 2nd edition has a 35¢ cover price, but the pages are unnumbered. Half way down the back of the guy on the front cover, there isn't a diagonal scratch that obliterates some of Robert Crumb's cross-hatching.
SRUCC: Zap Comix Series
Comixjoint: Zap Comix Series
Comixjoint: Zap Comix #0, 2nd printing
Grand Comics Database: Zap Comix #0, 2nd printing