Yes, I wonder how loud the advocates of military action against Iran will be shouting when they can't afford to fill their cars up?
Iran is one of the major oil producers, removing it's oil from the world market will push up prices, but not by a huge amount.
However, any action against Iran will cause an increase in attacks in Iraq, likely reducing it's oil exports. It will cause instability in the market, and push prices up, and if Iran retaliates by attacking shipping in the Gulf, or with attacks on oil facilities in the Gulf, the price of oil could easily hit $150 a barrel. And the effect of oil at that price on western economies wouldn't be pretty.