According to 1980s Flashback, 1984 saw a median gas price of $1.21 per gallon. At that time, stamps were 20 cents and a dozen eggs were $1.01.
The U.S. Energy Information Administration (EIA) explains that the price per gallon of gas fluctuates with the price of crude oil. It's directly correlated with the supply and demand of crude oil-based products. The EIA goes on further to state that gas is typically higher in the summer seasons, when a more costly summer blend is sold. Supply disruptions can also drive the price of gasoline higher per gallon, no matter what season it is.