Depends what you want to do, how you want to communicate, do you broadcast / mesh, uni/bi directional, etc. It's a "how long is a piece of string" situation.
From cheap, slow, long range deployments like LoRa (100 devices sending tens of bytes) to satellite broadcast (any number of synchronised devices), and a few things in between.
From cheap, slow, long range deployments like LoRa (100 devices sending tens of bytes) to satellite broadcast (any number of synchronised devices), and a few things in between.