"how does a cheap/basically free relay raise money..."
Free relays becoming excessively (expensively) large is counter-productive to the future of the protocol. Nostr's first strength is decentralization.
Free stuff tends to bad incentives and thus bad outcomes. Like incumbent centralized social media.
That said, there's a need for some free relays: allow people to play with the ecosystem, before they get serious and put some $ into what they value.
What does a sustainable middle ground look like, that works for both users AND relay operators? Very simple...
Read for free. Publish+store for a nominal cost. But provide something equivalent to a free trial.
Let the market take care of a) pricing and b) punishing relays that get stupid with ads and other weirdness.
test: multicast
Not your keys, not your coins.
Not your relays, not your notes.
cross-client test
relay test