I'm not sure who told you that they need high humidity, but they don't. I keep several high humidity species, and I can tell you for a fact that Crested Geckos are not one of them. I keep my Cresteds in very well ventilated enclosures and I mist their cages once per day and they do fine...even when the humidity in the room is only 30%. You don't need a fancy fogger or mister to keep Crested Geckos.
The only exception is hatchling to 6 week old cresteds and I still only mist them once per day. I just keep them in containers with slightly less ventilation, so that they don't become as dry.
FYI...
Even with a true high humidity species (which does NOT include Crested Geckos) you still do not want constantly high humidity. What you would want is for the humidity to be nearly 100% for a couple of hours, followed by a gradual drying out period. If the humidity is over 60% for 24 hours per day, you're going to notice bacterial/fungal growth, which can ultimately lead to a sick reptile.
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Anthony Caponetto
www.ACreptiles.com