PayPal is of the largest global payment gateway solutions. They operate in almost every country including Argentina. It is easy to use and set up. PayPal has a very powerful API which can be used to customise the payments based on the merchants requirement.
Paymentwall international payment gateway charges the lowest transaction fee in Argentina. Paymentwall has no setup or monthly payments. It charges 3.9% + $0.30 on every successful transaction on VISA, MasterCard,Payment Gateways (Argentina)