I wouldn't say it's easy if you haven't gotten into Facebook ads yet. Unless you use your real personal account with a real credit card. Otherwise, those who sell accounts most likely "farm" or "create fake credentials" under dozens of accounts and furthermore tries to sell them anywhere to make profit. They have a high cost to their names because they probably need to buy a residential IP or a very great proxy AND a legit bank card or a verified PayPal. Not to mention, residential IP's are probably the most expensive. They could cost thousands per month depending on the area.
Not for just one account, though, as I said they need to have those for every account they decide to farm. Verifying a PayPal under a fake name costs hundreds, you need a fake photo ID, fake SSN card, fake proof of address which adds up to be over $200. And getting a real debit or credit card from a bank especially under a fake name is illegal and could cost hundreds as well. I wouldn't recommend doing that, otherwise, if you do, you could buy from a seller here that does that for people that would like to verify documents and other stuff.
That's basically it. Hopefully, I explained everything. If not, anybody feel free to expand if you'd like.