1st print September 1977 has 0.75 USD cover price.
2nd-3rd print have 1.00 USD cover price. 4th print has 1.25 cover price. 5th print has 1.50 cover price.
Format changes - see issue #3[Revised].
6th print has 2.00 USD cover price. 7th print has 2.95 USD cover price. 9th print has 3.25 USD cover price.
Possible 2.50 USD cover price? Later printings with greater than 3.25 USD cover price?