You have 3 options:
1. Renting a GPS From Your Car Rental Company:

You can either arrange to pick up a GPS from the local car rental company or, you can book a GPS with our vendor that is pre-loaded with maps, in English, and sent directly to your home! Call our Customer Service agent and request a quote.

Cost: You will pay about 14 euros per day to rent a GPS from the car rental company. VAT included, paid locally.

Note: If the GPS is shipped to your US home it will arrive up to 2 days prior to leaving for your trip. You will be required to return it back when you return back to the US (one day after). The payment is made through Auto Europe`s website, shipping and handling cost about $40.00 and then you will be charged $1 per day for the GPS and $1 per day for insurance. For more information about your options for GPS rentals, please speak with our Customer Service agents.

2. You Can Take Your Own GPS: On eBay and Amazon you can purchase refurbished portable devices with Europe and North America maps for as a little as $50.This option offers ease of use as you will not need to learn how to setup and use an unfamiliar device.

100% Availability: Portable units rented in Europe are not allowed on international one-way rentals, and sometimes not on domestic one-ways. Many rental offices in smaller towns don`t even rent GPS.

Unlimited Coverage: A large percentage of rental car factory-installed and portable GPS units cover only the country in which the car is rented. That`s not a problem when you bring your unit with the right maps.

3. GPS Alternative: Use a Smartphone or Tablet

An increasing number of travelers don`t bother with GPS at all; they simply rely on Google Maps on a smartphone or tablet. That, of course, means if you want turn-by-turn live directions, you`ll have to have a data connection in the car, and that will involve cost. It may be worth it to you to purchase a data package from your phone`s service provider (ATandT, Verizon, etc.).

Another option that is less flexible but a cheaper alternative is to create and download maps of your routes prior to getting in the car when you have access to WiFi. Even without a data connection you can use the maps you downloaded and your phone will track your location using satellites and cell towers. Apps, such as OffMaps for theiPhone, can store multiple downloaded maps.

Finally, back up whatever navigation system you use with quality hard-copy maps scaled at 1:200,000 or 1:150,000 (preferred). The paper maps will provide a different perspective, identifying scenic roadways and significant sights and towns along your route.