The jar i brew in cost me around $20 dollars. Distilled water costs about .99 a jug (Austin's water is treated with chloramines that could harm the good bacterias and cannot be dissolved from the water) Tea ranges in price and i use about 8 bags per gallon of water. Sugar is pretty cheap - I should get organic, but i'm pretty cheap too. So all in all it was an initial investment but has paid off.
I use the continuous brewing method so i can siphon off as much or little as i want each day and add more sweetened tea to continue the process. I like to bottle my KT with some flavorings: dried cherries, cranberries, cinnamon sticks, cloves, ginger, fruit juice - whatever youlike and keep it in the fridge until i'm ready to drink it, or until one of my lovelly friends and co-op members stop by to purchase some. My little co-op is a great way for me to offer fresh Kombucha to locals at a cost much less than in the stores ($2.50 per 16 oz or just $2 if you bring me a jar to fill or in exchange). They get great tea and i get help purchasing the supplies to make it.
I recommend Kombucha to anyone looking for a healthful tasty beverage who has a little bit of time and a warm spot in the corner. I'll even send you a SCOBY of your own in some starter tea if you compensate the shipping and handling.