Make your own, it’s easy. Sort of like making homemade root beer. Plenty of recipes on the internet and Ebay has the starter kits.
http://getkombucha.com/reforkotea.html
Oh I know, but I don’t like the whole idea, it’s like making Greek Yogurt, you can do it but sometime it’s better if you don’t. Shoot, I can’t even make a decent biscuit and I’ve had the best southern cooks in the world try to teach me......hockey pucks!