Until I got this thing, my monthly Pierre water bill was $60-80/ month!
I do not like soda, but really like plain old carbonated water(Seltzer) and drink it by the gallons
I only drink four beverages(ordered by consumption): Seltzer, coffee, tea, and alcohol.
I found a home carbonating device from Soda Club USA that is fan-friggin-tastic:

It uses refillable CO2 tanks to carbonate water one liter at a time.

Plus you can vary the carbonation to your liking. I like mine at a steady boil!
I got one on sale with two CO2 tanks for $129. CO2 tank refills are $20.
My 14 year old son drinks about as much Seltzer as I do so our Seltzer bill is about $25 per month.
*BURP*!
PS If you order one, use this promotion code for 10% off your entire order: GIBSON10
I always Google for discount codes before I buy things online and found this one the first time I ordered CO2 refills.