Mastercard/PayPal
 

I'm currently making arrangements for a trip to South America. In some cases I have to use a travel agent, i.e., in Peru and Argentina, because train tickets can't be bought on line, or internet credit-card purchases are not easily made in some countries. The Peruvians want me to fax a copy of a credit-card authorization form along with a copy of my credit card, which is no problem; I've done that in the past. The Argentinians want me to pay using PayPal and Mastercard. I see on the PayPal website that this arrangement exists, but I wonder if it is safe and common. Any comments/experience out there?