Meshtastic is a great project which can be used in a variety of ways. One of these is to create off-grid mesh networks. Meshastic should not be confused with Mesh Net software which directly links phones together via onboard WiFi or Bluetooth. Meshtastic devices are a separate means of accomplishing mesh networking. This video helps explain the meshtastic approach to mesh networking Here's the link
https://www.youtube.com/watch?v=gqAsWtIjHUY
The 915MHz ESP32 LoRa OLED 0.96 SX1276 Transceiver Module + LoRa Antenna U.FL IPEX to SMA + 2P 1.25mm Connector for Arduino LoraWan IOT (Pack of 2)
are on amazon.ca ... $68 for a pack of 2
Power supply options....
These devices use public domain frequencies, 915 mhz and limited to 25mW. A 6db antenna is permitted.
At 10V input voltage, the current draw was 0.099 A (or 9.99mA). – 0.099A = 99mA
At 5V, the current draw was a little higher, at 0.128 A (or 12.8mA). – 0.128A = 128mA
https://techexplorations.com/guides/esp32/begin/power/