PPP is a type of pricing where the regional price is determined by the purchasing power of the corresponding currency, thus eliminating the different price levels between countries.
This usually doesn’t bother you if you live (mostly) west. Paying in GBP, USD, EUR, and JPY often means another living level. 1 USD in the USA is worth less than in an eastern Europe country, Africa, or Asia. Also, the inflation, pandemic, and financial crises beat the shit out of the other currencies.
I am happy that in the development field, when you want to buy a course, it is fundamental that there is PPP 👍. I would be happier if this trend were more broad and global.
To see the exchange rate for power parity pricing, visit the related OECD site.