I have a little dripper and a homemade one. They both work the same actually.
Making your own is probably cheaper (buy some PVC joints & pipe, a litre of soda, and a little valve) but buying a big/little dripper from a pet store is just as good.
Review of little dripper/big dripper; Has a handle so you can hang it off basically anything with a hook, or just set it on top. Holds quite a bit of water. You can control the drip speed with the plastic valve, and if you want a more specific drip you can also shove the plastic tube that comes with it into it, and put it through the top of the cage (allowing your cham to have a little tube to drink out of). Really convenient.