Facebook’s ‘legit’ advertising for likes is actually kind of a fraud. I would advice against spending money on it; you will not only lose your money, at the end these bought ‘likes” will cause damage to your exposure.
Check out this informative video by Veritasium.
Moreover, as the video teaches us; there is no way to delete the fake likes should you get those. Facebook, of course benefits from this sad state of affairs.