I got this Ninja Thirsti drink system. Oh my oh my is this a game changer. Comes with everything you need to get you started on some amazing refreshing sparkling water. You can make it from a 6 oz to a 24 oz cup size. You get to determine the amount of fizz  also the best part you can choose one or two flavors to add. My kids have been drinking the water every day since we got this. Anything to help them get some water into them. The ninja Thirsti has amazing flavors to add and they actually taste good. My favorite is the summer strawberry with vitamins lemonade. So far we have made tons of 12 oz and more sized cups and the c02 is still going. So I'd say they make tons of drinks from one of the c02 bottles. I highly recommend this brand and product.  You won't be disappointed I promise.