Stop Snap updates on Ubuntu

You can "limit" downloads in several ways. You can limit downloading times. You can find everything related to Snaps updates on the documentation here.

To Hold Forever

snap refresh --hold=<time> <[optional]snap_name>   # time = forever, 24h, 45m, 30s works

To unhold it, 

snap refresh --unhold <[optional]snap_name>        # You can ignore snap_name and apply it to all snaps

Make updates happen only at a specific time

sudo snap set system refresh.timer=4:00-7:00,19:00-22:10 

And there are a whole lot of ways to stop, limit or hold Snap updates on the documentation.

Old fashioned way

Before snap refresh --hold=forever was a thing, you had to add 127.0.0.1 api.snapcraft.io to /etc/hosts