The on-sale date is the publication date reported in U. S. Copyright Office filings.

Early printings by the Print Mint. Later printings by Last Gasp with the Apex Novelty logo still on the cover.

Underground Comix are known for using different prices, covers (art or color variations) and/or interior content to distinguish between printings.
1st print has 0.50 USD cover. 2nd print has 0.75 USD cover. 3rd print has 1.00 USD cover.
4th print has 2.00 USD cover. 5th print has 2.50 USD cover (not listed in Fogel's guide)(published by Last Gasp).
6th print has 2.95 USD cover. 7th print has 3.95 USD cover.