You can also use a fish tank pump, air stone, plastic water bottle, tubing, and aquarium acrylic. Cut 2 holes towards the top of the water bottle on opposite sides, feed 2 pieces of tubing in each hole so that one tubes end goes down to the bottom of the bottle, and the other end is at the top. Then seal em airtight with the acrylic. Fill the bottle with water and put the lid on. Attach the end of tube that's at the bottom of the bottle (under the water) to the air pump, then run the other tube into your enclosure. Turn on the pump and this will supply a steady stream of moist air. You just have to refill the bottle every few days. In total can be made for about $15.