Where does cheap traffic come from?

So sometimes I can’t understand in any way how file sharing exists? Of course, I understand that the lion's share of their income is made up of users with paid accounts.

But how is it possible to provide the ability to download files up to 2 GB in size?

The cheapest traffic, where I generally saw, is about 2 rubles per 1 GB. After all, if you count, it turns out that each download of the file will cost 4 rubles. But how do file hosting sites get this amount on free accounts from each download?

After all, at least they do not work at a loss with freebies.

Tell me, please, who knows where such cheap traffic comes from?