Sodastream makes a remarkably similar energy drink syrup for their Soda Stream system.  If that's part of your daily routine, this will easily save you hundreds of dollars.  If you just drink soda... well you don't save as much money, but you do get to make healthier drinks and cut down on environmental waste.

I saw and tested this at a Bed Bath and Beyond, and it's pretty impressive.  They've been around for a long time - in fact I think one of my language teachers used to have one in the 90s.