WhatsApp on iPhone was initially $1 to download, but had frequent sales. WhatsApp on other platforms was free to download woth a $1/year subscription... But subscription enforcement was uneven.

I started in 2011, and the subscription language was present, but there was no mechanism for payment. Then we put payment into Android, but frequently would extend all subscriptions. At some point the iPhone model flipped to match the rest, but if you had registered with iPhone before the switch, your account was set to lifetime.

I don't know the timeline, but towards the end there was a small list of countries where we would actually enforce loss of service for about a week when the subscription ended. After a week, we'd extend the subscription for a while anyway, because it was probably hard to pay (we tried to pick subscription enforcement countries where payment was readily accessible, but lots of people don't have a compatible mode of payment even if they have the means to pay)

We were told the company was cash flow positive, the public GAAP numbers look bad, but a large part of that is stock based compensation; a small part is accounting treatment for the lifetime accounts.

Also, it's important to note that the acquisition happened before real time voice and video calling launched and running servers for that was expected to be expensive.