Starting in August 2019, public subscriber counts will be abbreviated. For example, a subscriber count of 133,521 will show as 133k. You’ll still see your exact subscriber count in YouTube Studio
YouTube has scripts that can detect fake views and subscribers, and removes them. It'd be a waste of money to invest in something like that, and you'd risk having YouTube sending you a strike for violating their terms.
Websites like these are designed to make money, they lure people in and then ask them to prove they're human by completing a monetized survey. Upon completion of a survey, you won't receive/gain anything.