It seems expensive to get set up in every supported country https://support.apple.com/en-us/HT204411 https://support.google.com/googleplay/android-developer/tabl... with requirements for a business entity, money processing licenses, etc., and that's before hooking up to local payment methods (credit cards, prepaid cards, mobile top-ups) and paying their fees.

Paypal or some other large entity could probably do this, though.