I've started doing some hardware hacking as part of my new job, I'm amazed at what is available these days. This NodeMCU costs about $5, has built in WiFi, is programmable through the Arduino IDE and can be powered by a small solar panel. I'm blown away.
@kelbot@ajroach42 Yeah, if I was manufacturing stuff at scale I'd definitely go that route, but not for prototyping/hobby projects. I got a 3-pack of the NodeMCU off Amazon for about $16 USD, it's certainly worth the extra for the ease of working with them.