Looking for a Mother in San Francisco

I use to brew Kombucha back home in Baltimore,MD before moving back to San Francisco. When I was unpacking boxes my Mother didn't make the trip. I have wanted to get back into brewing, but am having problems finding a Mother. My first was gifted to me by a friend, but looking on craigslist everybody want $10-20 for one. I was hoping to get one gifted since there should be a million out there. Can anyone help?