With oil prices reaching multiyear highs due to reduced oil production in OPEC countries, Russia and elsewhere, U.S. motorists could be facing significantly higher gas prices this summer, says Patrick DeHaan, senior petroleum analyst at GasBuddy, a website and smartphone app that helps drivers find the best deals.

Motorists in some areas are already seeing gas prices of $3 or more, and that could rise further, at least in the short term, says DeHaan.

AAA reported today that the average price for regular-grade gasoline is now $2.66 per gallon compared with $2.38 a year ago.

more on Fuel Economy & Gas

Overall, DeHaan predicts that drivers could, on average, shell out an additional $100 to $200 for gasoline in 2018 compared with last year

The amount you'll pay depends, of course, on the gas station where you fill up. And the differences can be significant, says DeHaan. For instance, in Long Beach, Calif., he says there’s a Mobil station charging $3.79 per gallon for regular gas. But nearby, there’s a United Oil station charging $3.33 for the same thing. That’s a difference of 46 cents per gallon.

Fill up that minivan at the wrong station and you'll end up paying about $9 more than necessary.

And there are drivers who unnecessarily buy higher-cost premium gasoline for cars designed for regular fuel, according to a study by AAA. Based on current national average gasoline prices, mid-grade gasoline costs nearly 28 cents a gallon more than what you'd pay for regular.

Premium gas costs 53 cents more, according to the AAA, but DeHaan says that in areas like Chicago you may find premium $1.20 per gallon more than regular.

So if your car can operate on regular but you opt for mid-grade or premium gas, you could be paying $5 to $10 more to fill that same minivan's tank.

Tips to Spend Less on Gas

"If you're just looking at the price from the street, you're leaving money on the table," says DeHaan. There are things you can do to keep your gas expenses down. Among them:

Use a gas station app or website. GasBuddy, AAAFuel Finder, and Gas Guru are among the resources that can help you find lower prices.

You're also likely to get a better deal at stations that are not located on major highways, says Michael Calkins, a manager at AAA. Of course, making a big detour to pay less may not make sense.

Calkins also says to make sure that when you compare prices you consider only top-tier detergent gasoline, which is better for your car. 

Check the prices in the different states you'll visit. Prices can vary significantly because state gasoline taxes are different. DeHaan says he found that for a driver crossing the border from Ohio to Pennsylvania on Interstate 80, for example, it could cost 36 cents per gallon more to fill up in Pennsylvania. That's more than $7 extra to fill up the minivan's gas tank.

Think about how best to pay. Some stations offer a lower price if you pay with cash instead of a credit card. The difference between the cash and credit price usually ranges from around 10 to 15 cents a gallon, says DeHaan, though he says it can be as much as a dollar.

Another option is to pay with a cash-back credit card. While the credit card price may be higher than the cash price, the reward you receive could make using the credit card a better deal.

It's worth noting that a rewards credit card could even provide greater savings than a gas credit card from a big oil company (such as Texaco or Chevron), says DeHaan. For instance, the Bank of America Cash Rewards Visa card offers 3 percent cash back on gasoline purchases, among other things, up to $2,500. The Sunoco Rewards Credit Card, by contrast, offers only a flat 5 cents per gallon discount, though there is no limit on how much you can spend.

And if you plan to pay by debit card, don't assume that you are getting the cash price. Some stations could actually charge you the credit card rate instead. Check the posted prices at the pump. Selecting the debit option and entering a pin when you pump your gas is often a good indication your transaction will be handled as cash, says Lyle Beckwith, senior vice president of the National Association of Convenience Stores, based in Alexandria, Va.