One of the ways that Cloudflare actually earns money. No business can survive by giving everything for free
Argo is a service that dynamically monitors traffic to find the most congested and routes requests to them. It also deals with requests to certain Internet access providers such as the Australian Telstra, rather than forwarding it to Papua New Guinea and vice versa. ridiculous amount when Cloudflare tries to look at them directly.)
It also provides tiered caching so that if the local Cloudflare datacenter you hit does not have a cached element, this datacenter will ask for it at a nearby datacenter.
Argo Tunnel also allows you to secure your servers much more easily without having to deal with firewalls, etc.
Argo starts at $ 5 / month for the first gigabyte of bandwidth, then ten cents per extra gigabyte. In addition, Cloudflare has agreements with major hosts such as Microsoft Azure, Google Cloud, Automattic and DigitalOcean to reduce bandwidth costs for common customers.