It seems that if you're an existing iiNet or Westnet broadband customer and don't currently have a mobile plan then you can get $15 off your bill every month for 6 months if you sign up for a new moth-to-month mobile plan.
It looks as though you can cancel after 6 months with no penalty. Theoretically you could sign up for the $15 plan and get 200MB and $200 worth of calls and SMS for free.
Or if you take any of the other plans it's still pretty good value for a 4G service:
$30 becomes $15 for 1GB, $500 worth of calls and unlimited SMS
$40 becomes $25 for 2GB, $800 worth of calls and unlimited SMS
$60 becomes $45 for 3GB and unlimited calls and SMS
SIM only mobile plans
Our plans will work on 4G, 3G, and 2G networks, depending on coverage in your area and your handset’s capabilities.
Our SIM-only mobile plans let you keep your old mobile number, while giving you beefy call and data value.
And, new customers signing up before 2 December 2014 will receive $15 off their monthly bill for the first six months*. Our plans will work on 4G, 3G, and 2G (never heard of 2G) networks, depending on coverage in your area and your handset's capabilities.
*Normal monthly mobile fees apply after the 6 months is over, unless the 4G SIM service is cancelled.
Also for Adam internet