Don't go solely based on price, do a lot of research first. Make sure you can care for them, it is not a cheap endeavor for set up alone. Also, make sure you research the person/place you are intending on getting the chameleon from. I have never heard of any chameleons themselves to avoid, all will have their own personalities just like any animal or person.
I wasn't going to base it on price, and I realise it's expensive to set up, just wanted to make sure there wasn't a reason not to buy from him. He is new to breeding, not sure how to reader has him, or just go for someone that has been doing it longer, but then everyone needs to start somewhere