: You can order refills online; SodaStream sends full cylinders with a prepaid label to return your empties.

: Sites like Simpli Soda offer compatible exchanges for both screw-in and quick-connect types, often starting around $13.99 per cylinder plus shipping. CO2 Cylinder Exchange - SodaStream

Exchanging an empty cylinder is significantly cheaper than buying a new spare, often saving you up to 50%.