a low single-digit dollar amount of money isn't really prohibitive any more in almost all regions on the planet for a one-off payment (networked regions, at least). That's an argument facebook itself likes to make but if you look at the WhatsApp growth which used to have a model of 1$/year it seems completely fabricated.

And arguably a small payment amplifies anti-abuse measures because you have a hard financial trail. If a foreign entity buys thousands or more of accounts, not only are you putting a cost on it, it should be trivial to see the anomaly in the system.