Kendra,
It is not cheaper if you go the sodastream route. The carbonation refills will cost upwards of $20, because you are locked into their system..if you use a coupon at Bed, Bath Beyond, I think its something like $15. Buy a Primo sparkler instead and you can refill the CO2 at Dicks sporting goods, paintball shops etc for $3-4 a pop. A refill lasts me about 45days and I probably drink 2 liters a day.

I buy the soda mix with coupons too at BBBY and works out to like $3.33/syrup. You will save money doing it that way. You can use SodaStream, Primo or other flavors to make your drinks.

Going Sodastream route, it's about a wash depending how much you drink. I refused to be chained to their CO2 refill scam.

I got a 2nd Primo system on Living Social for $35! About the same cost for a 2nd CO2 canister and extra bottle, which was a great deal.

If you are a serious carbonation lover, there are other options to make your own CO2 for pennies, but it will cost more upfront and you would have to buy a 5lb or more CO2 tank and regulator etc. Most people won't want to bother with that.

I did a lot of research before buying one. IF you have any questions, feel free to ask. Yes, they do taste like the real thing to me. In some cases better.