Underground Comix are known for using different prices, covers (art or color variations) and/or interior content to distinguish between printings.
1st print 1968 has 0.35 USD cover price. Road in is yellow and sidewalk is white.
Page count is 24.
2nd print February 1968 - 3rd print May 1969 have 0.35 USD cover price. Road is brown with grey sidewalk.
Page count increases to 28.
4th print August 1970 has 0.50 USD cover price & says 'Fourth Printing' on inside cover.
Road is now brown with yellow sidewalk.
5th print December 1970 - 11th print 1974 have 0.50 cover price.
Believed to be indistinguishable from each other.
12th print 1975 has 0.60 USD cover price in red ink.
13th print 1976 has 0.60 USD cover price in black ink.
14th print 1978 has 0.75 cover price.