What is the marginal cost of adding Tier 3 protocol participation to existing institutional infrastructure?

A subsidiary question under Q-0004. The pricing comparison across architectural tiers turns on this number, because Tier 3 is the first tier whose marginal cost is structurally different — not lower-by-some-multiplier, but qualitatively different because the protocols compose with infrastructure institutions already operate.

The answer is C-0006. For an institution starting from nothing, a Hetzner CX23 node costs $36-$360/year depending on protocol class. For an institution with existing infrastructure — most U.S. R1s — the marginal cost is closer to zero: a BitTorrent seeding daemon averages 9-14 MB resident memory; a Tor relay needs 512 MB and 10-16 Mbps (~0.016% of a 100 Gbps campus connection); Forgejo runs as a single binary at 100-150 MB; BitTorrent's WebSeed lets any web server function as a seed with no software modification.

Universities are already running these protocols at zero incremental institutional cost (TU Dortmund, TU Dresden, MIT, 45+ universities running Tor relays, Academic Torrents distributing 298+ TB).