soda stream cost alert

DW decided to buy a soda stream.  It works just like they say it does.  We have even mixed flavors to come up with new flavors.  Grapefruit cola for one.  You can adjust the amount of fizz in it too.  The problem is with the cost.  They say it’s cheaper, it’s not.  The cost of the syrup here is about 41 cents.  They don’t mention the cost of the CO2.  Add that cost and it come out to $1.83 for 2 litters.   You do use much less plastic, so it’s greener.  I like it, but it does cost more than the store brand soda here in AZ.