Seltzer bottles/soda siphons - recs?

I like mixing drinks with soda and hate buying a whole thing of soda water only to use a bit of it and have the rest go flat. The logical thing would seem to be to buy a seltzer bottle (aka soda siphon) and use only what I need. After the initial purchase the cost is around $0.50 per liter of water (1 charger usually costs 50 cents and will charge a liter from what I have read). Does anyone use one of these, and have any recommendations for me as to which one to get? I'd probably get a 1 liter size so it can stay in the fridge (that's okay right?) although maybe the 2L ones would fit, I'm not sure. I'd rather not spend hundreds on it - maybe up to 60-70 bucks but much less if at all possible.

Also, are vintage ones a bad idea? I have a feeling if they need parts it might be almost impossible to fix them now.

Thanks.

What about six packs of club soda/seltzer? They're usually on sale for ~$1.50. If you're concerned w/ sheer cost, it might be worth it. Aesthetically though, go for a seltzer bottle.

I buy those but they are rarely $1.50, usually more like $3-4 / 6 pack, which is ridiculous for what they are. Maybe if I see them on super sale I'll just stock way up and forget the bottle idea.

I have no idea about them at all. But one of my friend's parents had a nice bar when I was a kid. His dad would make us little soda drinks with a soda siphon; lemonade and whatnot. Good memories.

I've been looking for one of these as well. Love mixing soda drinks, hate the waste and price of little bottles. Searching Froogle turns up heaps of results, but any personal recs would be appreciated.

I have the ISI Soda Siphon and would recommend it. I believe it is right in your price range as well J. No experience with vintage ones fwiw.