Optus refreshed its plan offerings a little while ago to a new "My Plan" system which had a price-entry point of $50. That's pretty hefty if you're not a heavy user. Perhaps that's why Optus decided to introduce a new $35 tier today, perhaps? Here's what it gets you.
The $35 My Plan is designed for light users, and comes with 200 standard minutes of calls, unlimited SMS and MMS, and a paltry 200MB of data. This is a plan for your nana.
If you go over the plan inclusions, you can throw a $5 bolt-on at the service which gives you 300MB of data and 250 voice minutes.
Although, if you're doing it regularly, it might be worth upping yourself to the $50 My Plan which includes 450 standard minutes and 500MB of data and the unlimited SMS and MMS.
As Angus at Lifehacker points out: this isn't the best value for money. You can get much better value from Australia's slew of cheap pre-paid carriers these days.
The rest of the My Plan offerings are below. The $35 slips in at the bottom, obviously, but it isn't shown in this illustration.