Misting systems make things much easier for cham owners, especially if you want to go away for a weekend.
You can certainly own a chameleon without having a misting system but a good quality, reliable MistKing or Aquazamp system is nice to have.
If you have a Jackson's chameleon or other cooler area, higher humidity-loving " montane " type of chameleon, then they are almost a requirement and definitely a benefit to both cham and keeper.
If you're looking for a brand new system, they are sold by LLLReptile, Josh's Frogs, MistKing, Aquazamp and others.
These are all forum sponsors and you'll find links to each of their websites herehttps://www.chameleonforums.com/index.php?page=sponsors
Sometimes people get out of chamkeeping and sell their supplies on the classifieds section of the forum https://www.chameleonforums.com/chameleon-classifieds/ or you may find one on your local Craig's List or newspaper classified ads.
There is an excellent Resources section of the forum where you will find a huge amount of reliable info that can be difficult to find elsewhere.
On the left side of each resource page are links to more info about things like enclosures, feeding, health, caresheets about specific kinds of chams, etc.
Here's the intro page https://www.chameleonforums.com/care/chameleons/