it is very easy to make your own. start with 1 bottle of plain gts. put it in a white mouth jar, cover with a papertowel or piece of cloth and a rubber band and let it sit someplace out of the sun that is warm and clean and undisturbed. avoid places with smoke, incense, mold, etc., because they can mess up the culture. in 1-2 weeks a nice culture will grow. it is usually a sort of creamy white. when it's 1/4 to 1/2" thick you can start brewing. make just under 1 gallon of tea. most ppl use green tea, but i love using a mix of decaf green and herb teas, especially hibiscus. strain the tea, add one cup of sugar. i use raw sugar and it works fine. when the tea has cooled to luke warm add the culture and the leftover gts. cover with a papertowel or cloth and set in a warm undisturbed place for 7-14 days. within 24-48 hours there should be little bubbles forming, showing it is fermenting. i use a sun tea jar so i can check the taste without disturbing the culture. start checking after 7 days to see how it tastes. when the balance of tart and sweet is where you like it take out the culture and 1-2 cups of the tea to start a new batch and put the done batch covered airtight in the icebox. mine seems to get fizzy after it's been chilled and covered about 24 hours. if it stays flat i add a spoonful of sugar and stir well, and it gets fizzy in a day or 2. i love making it. i haven't noticed health benefits aside from not getting as cold at night when i drink it, but it tastes wonderful. i love it when it's tart and fizzy and glowing red (from the hibiscus). one of my friends calls it fairy tea. when your culture gets too thick just peel off a layer and use that. sometimes the old culture will sink and a new one will form. you can pass along your extras to someone who needs one (it will still work fine) or store them in some kombucha in a covered container in the icebox as a backup. (if you use hibiscus in your tea, your cultures will be pink, but they work just the same.)