Kombucha, like any other living thing, has a strong will to survive. If you start out with a bottle of store bought raw, unpasteurized Kombucha (you know the kind), you can get a fully functional mother culture within a week. It's cake. In fact, you would probably have to try pretty hard to NOT get a fully functional mother.
Also, if you are into things like taking down the man and Thoreau, this is a baby step to self reliance. Almost.
Step 1: Materials
1. A bottle of raw, unpasteurized Kombucha. I won't name names, I'll just say avoid the kind with juice added. I started mine with the ginger flavored one, but that wasn't my first choice.
2. A clean glass jar, preferably rinsed out with boiling water prior to use. Preferably a small one with a rather narrow throat.
3. Tea. Black or green, as long as it's got no additives. I used some kind of green tea in a tin with no English writing, and it worked just fine. My last culture I did with black tea, worked just fine.
5. Cheesecloth or similar cloth. I use sterile gauze I pilfered from a first aid kit and it works just fine.