The other option is to buy a used GPS unit off your local Craigslist. One with Europe maps. (Or, if you're really a do-it-yourselfer, there are ways to add the Europe maps in yourself.) Personally, I like Garmin better than Tomtom. There are tons that are "reasonably priced". No need for the super fancy units, even the most basic ones will do what you want.

After you're done, re-sell the unit on CL at the same price or at a slight loss.

Either way, you're miles ahead.