It's easy to become the patron of Pepper&Carrot for only $1 per new episode on Patreon. Patreon accepts credit cards from all around the world and also PayPal.
The most popular patronage service for supporting webcomics artists, you probably already know it.
A libre alternative to Patreon designed for more privacy and lowest transaction fees.
An alternative to Patreon using €uros with an interface translated into French, Germans, Spanish.
The well known payments system that supports online money transfers with many available currencies.
Free of charge within Europe and works world wide:
Here is an adress where I'll receive your boxes and letters:
David REVOY au Cabinet Dentaire
135 Avenue des Mourets