Hey there @diegoleonprado !
It's unfortunate gift cards are not available for purchase in your country. Spotify always tries to have gift cards available everywhere, and if you can't find them in the stores right now, you may be able to find them in the future.
There isn't any other known way of treating others with Premium, all other available payment options for users and region is available on the upgrade page. Hopethis helps 🙂