Now that the twins are drinking cow's milk, we go through 5-6 gallons a week. That's a lot of milk!! I think it would be cheaper for us to buy a cow! They don't go anywhere without their sippy cups, and they are very particular about which cups they like. They prefer a certian brand, size and straw. Of course, the type of cup they like is not widely available. Drew and I have had to do quite a bit of searching to gather enough sippy cups for two babies.