What are offers?

Question

contextual advertising

I often see services that offer subscribers, followers, etc.
Today I saw an ad, they say 5tys. subscribers for 4500 rubles.
It turns out that one subscriber is cheaper than a ruble. What is it and how is it possible? What are offers?
And if people sell them cheaper than a ruble, then how much do they buy them and where?

Answer 1

such "visitors" are only to the detriment

Answer 2

Most of these services use:
a base of real users who receive some pennies for joining groups.
base of real users formed according to the principle of a pyramid (for likes, it happens) base of real users
attracted by recommendations from broken / fake accounts
ways that unidentified youth and not so youth will buy)
fake accounts.
a lot of different people.

Answer 3

These are subscribers, followers. These are not real clients.
They are needed in order to increase the popularity of your public or channel on YouTube. And then this popularity will bring real interested readers.