No check your DM i just send you The Nostr Basics . #Amethyst

https://bevstr.com/Nostr/

for the most part relays are free but when you pay, you pay for relays

clients don't have a scheme for billing designed yet, this would be a good thing to, for example, keep damus iOS on the App Store

No, the app is totally free. Just some relays ask a one time fee for writing notes on it, but you can choose which relays you want to be connected to, most are free, you can donate btc to the owners or devs