Just looked it up. Bought both the hose and machine off Ebay. July 21, 2019. So it looks like a 20# bottle $25 fill of CO2 will last us about two years. Price of CO2 may be higher than that now, that was a couple years ago. If my guesstimations are right that fizzes 400-500 gallons of water. Or about 4,000 or 5,000 12 oz cans worth of soda equivalent. Around a half cent a can for materials cost??? Another half cent of RealLime juice splash???? So maybe a penny a 12 oz can equivalent for "flavored soda" cost. Not counting initial equipment expense of course.

I give $160 for our refurbished KitchenAid. Not sure why they have gotten so high priced.

Here is a brand new one.   https://www.ebay.com/p/27006800322?iid=132756928950
More than most people want to pay for a soda machine, but we do use the heck out of it. And I know of at least one wife that has a big KitchenAid mixer and a Breville food processor (plus some other pretty nice kitchen stuff). But her kitchen stuff looks cheap to some of my toys. :-)  So I never complain.

Other brands I am sure would work just fine.

I think this is the wire braid hose we got. 36"   https://www.ebay.com/itm/303793568254?hash=item46bb81f9fe:g:ZeIAAOSwoZlbyTzA

Not recommending this to anyone. Just what we did in case anyone is interested.