It costs the average Russian nearly two day's wages to pay for ProtonMail Visionary. It costs the average German just over two hours.

Average wages vary drastically throughout the world, which is why large international companies like Spotify accomodate poorer nations. The same Spotify premium plan is equiv to USD 18.42 in Denmark compared to USD 4.50 in Argentina. This opens up their market to a global audience who would otherwise be unable to afford their service.

So what can we do to prevent someone in Switzerland paying for ProtonMail in Mexican Pesos?

Global issuer identification numbers: the first six digits of every single Visa, MasterCard, Amex issued is associated with the country of issue, the card type (credit, debit, prepaid), and the bank that issues it.

This would stop an Australian with a 375414xxxxxxxxx paying for the service in Russian rubles.

This can be gradually rolled out country-by-country for simplicity.

PayPal, Bitcoin, mailed cash payments could all be linked to CHF as-is now.

Sources:

* Wages: https://en.wikipedia.org/wiki/ListofEuropeancountriesbyaveragewage

* IIN database: https://binlist.net/

* Spotify Pricing: http://mts.io/projects/spotify-pricing/

* Stolen idea: https://www.reddit.com/r/ProtonMail/comments/5pgnz3/adjustedpricesfordifferentmarketsandlocall/

* https://en.wikipedia.org/wiki/Paymentcardnumber#Issueridentificationnumber_.28IIN.29