Game Hangout · Minecraft
Java Edition, Fabric mods from Modrinth, and the world lives on whoever's PC is on. No Realms, no rented box.
Free. No account. Server files: ~235 MB, once, on the host's PC.

The server itself: the ~235 MB download, once, on the host's PC; the tunnel to your friends instead of port forwarding; and the world that follows whoever starts it next. For your group it feels like a server that is always on, without anybody renting one. Fabric mods from Modrinth, picked in the app and shared in the session, so everyone runs the same set.