E.g. in CH also at Sodabaer.

Migros, COOP, Lidl, compare, as there are large price differences of up to 100%.

Everywhere there are cylinders :) Shop or online, e.g. directly from Sodastream. They are the same cylinders. They have a deposit on them, so you get a new one without paying a deposit when you return an empty one.

We always go to Migros to exchange them. But Coop should also offer this service.