As Americans hit the road this summer, many will drive rental cars in other parts of the country or the world. While rental cars can be convenient, the associated costs are often confusing. Here's a look at car rental mistakes that could cost you money -- and how to avoid them.
1. Buying extra insurance you don't need. If you have your own auto insurance policy, it may cover collision damage and personal liability for temporary use of a rental car (but likely not a moving truck). And if you use a credit card to book and pay for the rental car, it may provide secondary collision coverage. "The credit card coverage will kick in for anything your personal policy doesn't cover, and you don't need to pay your deductible," says Brian Karimzad, the director of MileCards.com, a travel rewards card comparison website. "Check on that before you rent a car, and you may be able to decline that coverage at the rental car counter."
On the other hand, if you don't have your own auto policy or you're concerned about potential premium increases should you need to file a claim with your auto policy, the car rental company's insurance may make sense.
[Read: 5 Insurance-Buying Mistakes to Avoid.]
2. Renting from an airport. Renting from an airport often means airport surcharges. To avoid these fees and possibly bag additional savings, Teri Gault, CEO of TheGroceryGame.com and author of "Shop Smart, Save More," suggests choosing a car rental service away from the airport. "Many off-airport rental offices provide transportation to and from the airport," she says. "And it can be more convenient than booking at the airport and having to take a rental car shuttle and dealing with huge crowds."
3. Not shopping around. Car rental rates can vary depending on the company or the amount of lead time, so it pays to shop around instead of taking a "one-and-done" approach. Websites such as CarRentalSavers.com and AutoSlash.com allow you to comparison shop between rental companies and look for coupons. AutoSlash will even track your rental rates and rebook for you if the rate drops.
If you're planning to drive long distances, check for mileage caps. "Many rental companies offer unlimited miles for the car rental period, allowing you to drive the car as much as you want without facing extra fees," says Angie Hicks, founder of AngiesList.com. "But others may assess extra fees for surpassing a daily mileage maximum. If you rent a vehicle, especially for a period more than a few days, make sure you have unlimited miles or sufficient miles to cover your travels." When choosing between a rental with unlimited miles and a cheaper rental with a mileage cap, you may come out ahead with the former.
4. Prepaying for gas. Prepaying for gas may seem convenient (who wants to plan extra time for a pit stop on the way to an early morning flight?) but it means you'll pay for a full tank of gas, even if you return with the tank half full. "It's better to fill up yourself since you can usually find cheaper gas prices at a nearby station anyway," says consumer and money-saving expert Andrea Woroch. "But don't forget to fill it up because the cost to do so after drop-off can be a total rip-off." Be sure to top off the gas, because some companies will charge you even if the gas gauge is just a hair away from where it should be.
[See: 10 Unexpected Costs of Driving.]
5. Paying extra for GPS or a car seat. Car rental companies are happy to charge you extra for accessories like a GPS or child car seat. But as Woroch points out, a GPS can cost an additional $10 per day or more. "Use your smartphone when possible, or print directions using your hotel's free business center," she says. If you have a portable GPS you could pack in your suitcase and use on your trip, remember to remove it from the rental car on your return.
According to Sarah Schlichter, senior editor of IndependentTraveler.com, many airlines will allow you to check a car seat or use it on the plane for free, so you don't need to pay extra to use one from your rental car company.
6. Rushing through the inspection. Thoroughly inspect your rental car before you drive away. Otherwise, you might be charged for damage you didn't cause. "Most rental car fleets are maintained meticulously, but damages like scratches or dents in the body or spills, stains or tears in the interior can go unnoticed," Hicks says. "If you see any wear, damage or defect during the inspection, make sure you immediately make the company aware -- or you might end up paying for it." Never assume that a ding is too small to warrant noting or that the car company already knows about damage. If it's not listed on the car condition form, speak up.
7. Returning a car late. Most car rental companies charge daily rates based on 24-hour periods. "While some may give a 29-minute grace period, you may be charged late fees -- or for a full extra day -- if you return the car past that time window," Schlichter says. Allow plenty of time on the day you're returning your car to avoid this extra fee.
[Read: The Hidden Costs of Rental Cars.]
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