This is a great early article about the monetization possibilities of relays from nostr:npub17vfczefc56xsh920rtkfad0t347xc8j5llta3wvs8hglq8sxycxst57j5y

https://andreneves.xyz/p/the-rise-of-paid-nostr-relays

Since then several paid relays showed up, most popular probably nostr.wine, and they are playing and creating the market.

Currently it looks like there's severe imperfect information on this market, and there's wild guesstimation about what price to expect for what service, and how to implement in a sustainable business model.

Tldr, solutions come to the problems.