I buy my lemon and sugar at ALDI, so a 5 gallon batch costs me under $12 and that includes the bottle caps at a penny each. I often use a slurry from another wine to start the batch, so there's no yeast cost and I buy the ingredients in bigger packages which seems to be much cheaper/dose than the little bottles. I bottle in 12 ounce beer bottles, so the cost is less than 25cents per bottle. Officially, 12 ounces is probably two standard servings of wine, so that brings it to 13 cents a serving.