Where to acquire the makings of a do-it-yourself soda fountain? Seltzer bottles (soda siphons) can be had at most Target stores, or on the Target web site. Places like Williams Sonoma have them, but you can pretty much guess what the main drawback is there: price. At a discount store, you can expect to pay about $40 for a serviceable model (an iSi or a Liss), but if you intend to get serious about it, you might consider paying up for a premium model like a Mr. Fizz. They’re expensive ($100 or more) but contain top-quality parts (no plastic pieces) that’ll last you a lifetime.
Concerning ingredients, the main thing you’ll need that you won’t find in stores are syrups. Pretty much all carbonated beverages are sold pre-mixed these days, so if you want to make your own fountain Coke, you’ll have to mail order or go to a local food service distributor. Clearly the big restaurant-sized tanks are right out for any normal person, though it is possible to find soft drink syrup in boxes that are intended for use in smaller machines.
But then nobody says you have to go name brand. There are a lot of knock-off cola, lemon-lime and root beer syrups out there that taste almost identical to the name brands. I like this place, Prairie Moon, not necessarily because their soft drink syrups are good (though they are) but because they’ve got all the flavors too: the chocolate, cherry and vanilla syrups without which no soda fountain would be complete. But look around for yourself. You’ll be surprised at what’s out there for the aspiring soda fountain freak.