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:

Getting Started | Meshtastic

The official Meshtastic guide to get you started. Covers all devices and configurations.