Renting a car in another country presents obstacles aside from the ones on the road. Your car insurance at home generally won't protect you abroad. Adding on insurance can double the cost of the rental. "Insuring yourself against a mishap is very expensive," Richardson said. "Let's face it, that's one of their income streams."
Many car companies also charge extra for a GPS or if you add on a second driver. "While big car companies like Hertz offer discounts, to AAA members for example, small local companies may be more willing to negotiate on the extra costs," said Susan Farewell, founder and CEO of Farewell Travels.
And check whether the rental company requires you to have an international driver's license as well (in addition to your regular license). If so, it will need to be obtained in advance of the trip and will add another $20 per person plus the cost of passport photos.
Finally, before you get behind the wheel, familiarize yourself with the rules of the road, like whether the headlights must remain on, and how to handle tolls. In some countries, like Austria or Switzerland, you'll need to purchase a vignette, similar to an EZ pass – getting caught without one is a $100 to $200 fine.