It depends on your comparison point. Compared to bottled/canned soda, you're right that there are high up-front costs and an eventual break-even point to using

It depends on your comparison point. Compared to bottled/canned soda, you're right that there are high up-front costs and an eventual break-even point to using a SodaStream. Compared to the more DIY version of buying a CO2 tank and the proper fittings to carbonate a 1- or 2-liter bottle (all easily found at a homebrewing store), the opposite is true: the initial buy-in of a SodaStream is about half the price of a CO2 tank and dual-gauge regulator, but refill prices for a 5lb tank are pennies on the dollar compared to SodaStream's refill cartridges. SodaStream's ultimately a razor and blades business model.