[grkvlt]

So, something like AX.25 [0][1] on the amateur radio VHF and UHF bands, which is free (once you have an appropriate license) and there is widespread citizen maintained and managed infrastructure, such as repeaters. [2]

0. http://www.ax25.net/

1. https://en.wikipedia.org/wiki/AX.25

2. https://ukrepeater.net/