I made a tank humidifier from an ultrasonic humidifier off Craigslist for $10. Got the tubing and connecting parts from home depot for under $10. It's not automatic, but works well when I'm closing up the cage (lost humidity) after handling the snake. I think I saw some cage humidifiers from ZooMed that work on a schedule. They run about $70-$80 and put out fog. I have a glass cage with foil covered top, and coconut substrate. My humidity is not hard to control, and I live in the desert. I check it nightly using digital temp/ humidity gauges. I have one one each side, and add as needed. The more experienced folks may have ideas about hooking one up to become more automated.