What are you looking to do?

Fiddle around with a prototyping board that you can add sensors to? 

Send/receive on an established mesh with an all in one handheld unit? Or use phone for interface?

Increase your local mesh with a solar-powered base and a big antenna?

The Meshtastic website has a lot of info:
https://meshtastic.org/docs/getting-started/ 

 Thank you.