Plenty of ways around that, like prepaid debit cards, using stolen credit cards, etc.

How do you think scammers pay for things? It’s with other people’s credit cards.

Depends if they already scammed some payment details.

Stolen credit cards.

Also, the $8 price will make it useful for card testing, the practice of checking whether stolen credit cards work.

I've worked at places that had to implement policies limiting features for a while because scammers would use credit cards that would turn out to be fraudulent. I don't know the details of how they worked it out, but they could sign up, send SPAM via us, and then the account would get shut down a week later (and we'd get a huge hit to our deliverability because of their SPAM).