Normally where you bought them

Online at Perfekt Draft which is expensive or at beverage retailers. Sometimes famila also has them. It's best to buy them with a crate, otherwise you can only send them in to Perfekt Draft. Amazon also has them

We do not sell the beer. You need the official Philips PerfectDraft cannisters.

Yes, you should cool it in the fridge first, that's what I do, because when it's warm it takes 3-4 hours. And about electricity: unfortunately I can't tell you exactly, but my electricity bill hasn't changed as a result.

The beer remains drinkable for 30 days, provided, however, that the system remains energised.