In todays MX (you get at train stations in Sydney and Melbourne) on page 8, they have a voucher so you can get a FREE LARGE slurpee @ 7 eleven.
I just got one just then. They accepted it straight away.
Also when you get your free slurpee - DONT FORGET to ask the store guy for your extra membership prize. When they enter the barcode to get your FREE large slurpee, a reciept is printed with a SECOND FREE PRIZER!! You can win a free killer python or cadbury boost or a free medium slurpee too.
I got my FREE Large slurpee and then on the reciept won another FREE medium slurpee!!
P.s. I can confirm they are doing this with Sydney and Melbourne MX on wed 20/5. Not sure about other states….