ishfaque

Well, I think it is better to think of it more fundamentally.

We know generally: If price falls demand increases. If price rises demand decreases.

Demand elasticity simply measures how much the demand changes, i.e. its sensitivity to price.

We know generally: If prices rise, supply increases. If prices fall, supply decreases.

Supply elasticity simply measures how sensitive the supply side is as a result of price changes.

Elasticity attempts to explain how sensitive demand and supply are to changes in price.

I don't think a gas station owner in a competitive market (competing with other gas stations) really relates. You are just substituting one guys gas for another's guys gas, which doesn't change elasticity of gasoline in the aggregate, only who it is purchased from.