I would avoid fake followers like a plague, unless it's a throwaway FB page.
The best 100% natural (slow) method I have seen so far was from Neil Patel. He advertised for page likes on FB to English-speaking audience outside of the expensive markets (US, CA, AU, UK) in countries like India, Pakistan, etc. Once he got a 1000-or-so cheap likes, he started doing promo exchanges with non-competing pages that cater to his desired audience. Along the lines of "If you liked my page, you will surely like [partner page]". He needed only a few months to get to 50k likes, using this method.