kombucha is also REALLY good and pretty easy! and once you scale up a little bit you can have basically as much kombucha as you want for mere pennies. way better than the $/bottle at the grocery store or costco.
Second this. I'm a fairly experienced cook and I was surprised at how easy it was to make kombucha using a bottle of organic kombucha to grow a SCOBY. /r/kombucha has some good starter recipes.
The only important thing I can think of is to be scrupulously clean.
