ISP shittiness aside, ISPs do actually pay for Internet backbone access by the byte. Usually there are peering agreements saying “you take 1tb of traffic from us, and we’ll take 1tb of traffic from you”, whether that traffic is destined for one of their customers (someone on Comcast scrolling Instagram), or they’re just providing the link to the next major node (Comcast being the link between AT&T’s segment of the US backbone and Big Mike’s Internet out in podunk Nebraska).
And normally that works pretty well, until power users start moving huge amounts of data and unbalancing the traffic.
ISP shittiness aside, ISPs do actually pay for Internet backbone access by the byte. Usually there are peering agreements saying “you take 1tb of traffic from us, and we’ll take 1tb of traffic from you”, whether that traffic is destined for one of their customers (someone on Comcast scrolling Instagram), or they’re just providing the link to the next major node (Comcast being the link between AT&T’s segment of the US backbone and Big Mike’s Internet out in podunk Nebraska).
And normally that works pretty well, until power users start moving huge amounts of data and unbalancing the traffic.