Got bought the gizmo for xmas but I'm still reluctant to pay £2+ for a can. Don't really drink much anyway- especially at home. Grandfather bought it me alongside a few of the incorrect surger cans so I still haven't even used it.
You can use the regular cans with it, just need to pierce the top with a pin carefully and slowly let the air out so you don't set off the widget inside the can. Once the air is gone just use like the nitro surge ones.
I just buy the regular Guinness pint cans now and use them, saves a fortune in the long run
This guy explains it well as it does have a nack to it. Takes him a while though for some reason, I can get the air out in about 10 seconds