Because I use only the main relay and it still works, with no recurring payment. They also have payment pages to add more time for filter and inbox, but not for the main relay. I couldn't find anything that states it in their docs, but I'm sure that's the way it is. nostr:nprofile1qqsrmpp2lmx4u2fl9zmxy7fnwp9rlwxwz5a2j8tep2c376n494z2gtgpzemhxue69uhkjmnzdauzumn0wd68ytnhd9hx2qgswaehxw309ahx7um5wgh8w6twv5q3wamnwvaz7tmrwfjkzarj9ehx7um5wgh8w6twv50uspzs?