Found this while looking around on Vodafone's website. Seems like it's a good deal. While it's $50 it does have a 60-day expiry period (=$25/month) which makes it comparable to (or better than) their $35 All-time plan or the $30 Cap, both of which have 500MB data.
This All-time plan has 1GB data, infinite text and calls any time while the cheaper $35 plan only has unlimited calls during off-peak periods.
And when recharging on My Vodafone, they'll double your credit (=$100) until the end of November: http://vodafone.com.au/personal/prepaid/home/options/all-tim…
I've been browsing on their site a few times recently and have just noticed this 60-day expiry. Might be a new thing as it still says 30-day expiry in the terms & conditions and in the upper link. This one says the 60-day expiry: http://shop.vodafone.com.au/all-plans?id=1700027
Update: this is a starter pack though, so it might not be as attractive unless you want to buy one every 2 months. Maybe move to forum?
$10 per month:
http://www.tpg.com.au/mobile/callrates.php?plantype=spstarte…
$18 per month:
http://www.tpg.com.au/mobile/callrates.php?plantype=spmedium…
Non-contract.
Way more value.