No demerits for the photo radar since they have no way to prove who was actually driving. 106 in an 80 is 3 demerits, I believe.
Here's how the demerit system works:
http://transportation.alberta.ca/2172.htm
It looks like you're allowed up to 15 demerits before your licence is suspended, and the demerits come off your record after 2 years (from the date of conviction, not the date of the offense).
If you go to the court house and talk to the Crown Prosecutor (follow the signs to the Traffic Court windows, and be prepared to wait for a couple of hours for a 1 minute meeting), you'll pretty much be offered a reduced fine/demerit reduction just for showing up.