Hmm, never had to pay an entry fee before in Argentina -- they say this one is new (we didn't have to pay it when we were there a year ago) and as of July, it has to be paid before you can even get on a ship or plane going to Argentina. We don't plan to spend any money there, so exchange won't be a problem--we're leaving the day the ship docks. When we were there a year or so ago, the guide on the tour bus was exchanging money at a much lower rate than the official exchange rate. We took the deal but managed to use it all on the hotel bill when we left.