This device, heltec v3, is basically as inexpensive as you can get and works perfectly well. The board itself is an ESP32 and is upgradeable with a better antenna. The ESP32 is not very energy efficient, so for low power & solar applications the RAK WisBlock devices are better. 

Lots of options here: 
https://meshtastic.org/docs/hardware/devices/ 

 Personally I think this outdoor solar node is really cool. Supposedly it will handles heavy rains well. I just need a high up location to mount it.

$100 on Etsy
 https://i.nostr.build/rVp2IAve9IfQYqdW.jpg
#meshtastic 

 need 

 Link? 

 https://www.etsy.com/listing/1777099913/mini-meshtastic-solar-node-for-fence?click_key=45295d35ce467aa2755d760224b84027b6107fec%3A1777099913&click_sum=456940e6&ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=meshtastic&ref=sr_gallery-1-1&organic_search_click=1&frs=1&sts=1&content_source=dd8503c30a68a95d56d5ab37d452d474cac0f363%253A1777099913