Q: What is the cost per batch using a TKS kit?

A: The only two items you need to purchase after the initial batch are tea and sugar. So the cost of each succeeding batch depends on the quality of those ingredients. The average cost falls somewhere around $1.50/gallon. You can get make it for less, you can make it for more, but that is going to be your average continual cost per gallon of kombucha.