Let's take a look at Meshtastic which leverages low-power LoRa radios to form ad-hoc mesh networks. No license is required, encryption is encouraged and all for under $30 bucks. The only downside is the range of a few blocks or a couple of miles. This can be overcome by deploying more nodes or designing high-gain antennas to meet your needs. Want to text your friends at the lake? No problem, just put up a base node at your campsite and give everyone a Meshtastic node with the Meshtastic app. If you have a phone with bluetooth, your almost there. Instant off-grid and secure messaging for everyone!