How can I pay with Argentine money?

Maybe PayPal.

edit: u Always can play demo if u like track and cars.

You'll need an international credit card as listed on the Shop, or other payment methods as for example PayPal like Maus said.

I hope in the long run LFS will have more pay methods apart from credit cards/PayPal added, which will benefit both customers and the devs themselves more.

Would be nice if LFS would support https://www.paysafecard.com .. Sure, it has 15% transaction costs; https://www.paysafecard.com/en/business/online-partner/pricing/ but it's globally available.

It has an API https://www.paysafecard.com/en/business/online-partner/integration/ and a lot of PSP support https://www.paysafecard.com/en/business/support/faq/details/which-payment-service-providers-does-paysafecard-work-with/