$3.00update. There are 12 Regular gas price reports in the past 5 days in Hays, KS. The average Regular gas price in Hays, KS is $2.38, which is $0.4 lower than U.S. national average Regular gas price $2.78. The lowest Regular gas price is $2.26 of Cenex-Midland Marketing Coop located at 201 E 8th St, Hays, KS 67601.he average Regular gas price in Hays, KS is $2.38, which is $0.4 lower than U.S. national average Regular gas price $2.78.