On the Optus network. for $15.50 you get a sim (or micro sim) + $500 calls + 5GB and 45 day expiry. http://www.woolworthsmobile.com.au/ I am picking one up to add to my Telstra Prepaid (which I picked up at Woolies for $10). Its a great way to test another network before locking into a 2 year contract. I have 7 months to go on my Voda contract, whom I have been with for 4 years, but its time to change and i need to test all the networks before locking into a deal. There is no reward for loyalty in the phone game, Telstra will give you a $200 credit for swapping to them, but you do need to wrangle.