How much formula??

We are expecting a baby through adoption the beginning of September and we will obviously need to formula feed. We went to Costco today to check the prices of formula and they range from $30-50 for 34oz.

Does 34 oz mean just the formula in the container, or once its fixed in with water? And I’m curious to know how much does a baby eat a day starting at newborn all the way up to 12 months?