We Americans have very short memories. When the price of a barrel of oil hit a record-high of $147 in July 2008, I took a ton of calls from people who wanted to dump their SUVs and buy a hybrid or other fuel-efficient vehicle. But as prices subsided, Americans resumed their love affair with bigger vehicles.

It's been the same trend with the sale of premium gas. According to the U.S. Energy Information Administration, premium gas sales dropped to an all-time low—7% of all gas sold in the United States—when the price of oil was at its peak in July 2008.

That's a big drop when you consider premium gas has accounted for up to roughly 20% of all gas sold in the last 20 years.

But now that $4-a-gallon gas doesn't seem too far away again, I'd imagine sales of premium are dropping -- though I haven't seen any official numbers yet.

Here's why you probably shouldn't buy premium gas for your vehicle

I'm here to tell you that premium gas is, for most people, an unnecessary waste of money.

Most cars will run just fine on regular gas—even a Porsche! And unless your vehicle specifically requires premium, using higher-octane gas may actually harm it. If you're not sure, just check your owner's manual to see what your car or truck needs.

Ultimately, you want to use whatever the manufacturer specifies, even if that means premium gas.

Also, you need to know that there's no difference in the quality of gas between a brand name and a no-name filling station. What goes into gas is regulated by the state, and price is the only difference between any 2 stations. So save your money!

How to comparison shop for gas online

When gas prices at wholesale drop significantly in short time periods, you'll probably notice there will be big differences in the price of a gallon from station to station in most metro areas.

The normal price ranges from 15 to 20 cents, but it's possible to see disparities of around 35 cent per gallon from station to station.

Why the almost double spread? It's all about delivery cycles and the volume of business at filling stations. Stations known as "pumpers" in the lingo of the trade may get 3 deliveries a day. By comparison, slower stations that don't sell as much gas may only take delivery once every few weeks.

So during times of falling wholesale prices, the high-volume stations cycle through deliveries every day and reflect market prices quicker and more accurately. Yet during times of rising gas prices, the whole cycle is reversed and the low-volume stations have the best prices because they're still selling gas from a week ago before the run-up in price at wholesale.

Pay attention to what prices you see as you're driving around and fill up when you see a deal. "Pumpers," in general, will be the best place to fill up. You can use websites like GasPriceWatch.com and GasBuddy.com to help you comparison shop for gas prices. Walmart currently has a seasonal promotion where you can save 15 cents/gallon in nearly 20 states.

But remember, it costs around 59 cents per mile to operate a vehicle, when you consider fuel, maintenance, depreciation and other factors. (See an exact breakdown here.) So beware of driving too far out of your way to get cheap gas. It defeats the purpose!

Improve your vehicle's fuel economy right now

Looking for some no-brainers that can improve fuel economy on your existing vehicle? The old standbys still apply.

We've all heard them a hundred times. But almost nobody remembers to do them—unload your trunk, keep your tires properly inflated, and slow down out on the road. Make a resolution and do these things! And the real twofer here is to walk short distances because it saves money and improves your health!

Image of Clark Howard About the author: Clark Howard

Clark Howard is a consumer expert whose goal is to help you keep more of the money you make. His national radio show and website show you ways to put more money in your pocket, with advice you can trust. View More Articles

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