The best option is to buy 2 gallons for $5.98 because if you do your work and check how much everything else costs for 2 gallons (example: 1/4 gallons multiplied by 8 equals $14.40 which is 2 gallons) you'll see that everything else is too expensive, and the 2 gallons for $5.98 is the best answer.
I hope this helps :)
