I just booked a Group Z "people mover" van with Dan Dooley (Thanks for all the advice, forum people!).
On the Confirmation, I noticed they had the Credit Card charged as $.
I remember reading on these forums that I should always charge purchases in the currency of the country you are in, to save fees.
Should I have charged the rental car in Euros? I booked it just now, so I might have time to switch it.