Vodafone $30 pre-paid - PROS: Unlimited calls/SMS
Vodafone's new offer out now includes unlimited calls and unlimited SMS/MMS with 1.5GB of data for $30. However, there are some things you need to realise about some pre-paid services like the one I've just mentioned. For Vodafone, you are not able to select an automatic recharge at the end of your month. You need to manually log in or call up to recharge each month.
Also, if you recharge, say, one week before your credit expires, you are double paying for that last week because the expiry date starts from the day of recharge, not from the last day of your last recharge (if you still follow). Also, when we are talking about a MONTH, it's only 28 days for Vodafone. This means that over the course of one year, you will end up paying for an extra month.
Optus $30 pre-paid - PROS: Data rollover up to 10GB
Optus calls a month, 30 days which is better than what Vodafone does. Their pre-paid plan includes unlimited mobile phone calls and SMS/MMS and 1.5GB. The big difference is that any unused data gets rolled over to the next month if you recharge before your expiry date. There is a maximum of 10GB that you can roll over to the next month. $30 prepaid now comes with a 5GB one off bonus.
Amaysim - PROS: Cheap introductory offer
Amaysim resells Optus 4G with their $30 prepaid service getting you unlimited calls and unlimited text with 2GB of data. If you are switching from another provider, use the promo code 3MONTHS when signing up to get this $30 plan for only $10 for three months plus get an extra $10 referral by signing up here (click on Show me the plans). One month is 30 days with Amaysim.
Telstra $30 pre-paid - PROS: Credit rollover
Then there is Telstra, offering their $30 pre-paid service, also calling their month 28 days (30 days if you choose direct debit on credit card). They give $250 worth of calls, unlimited text, unlimited calls to Telstra mobiles and 1.3GB data . Their credit, however, does roll over to the next month (data does not on $30 recharge). There are other options but in order to compare relatively like for like, this is the closest pre-paid service that Telstra offers which is comparable to the other two. Their $30 plan also comes with 5GB one off bonus data.
An interesting thing about Telstra credit is that you can use it for purchasing items in the Google apps store or iTunes. Head over to this link to find out more about the various other things you can do with a Telstra prepaid sim, such as using Mobile Foxtel for the first month for free.
Optus $1 per day pre-paid
If you are not into the smartphone thing and you're happy to turn down your data usage to an absolute minimum, Optus has a $1 per active day plan. This gives you 30 minutes of calls each day (and if you go over this, they will just charge you another 50c for that day for unlimited calls). You also get unlimited SMS but only 40MB of data to use each day. If you don't call, text or use data for any given day, you don't get charged for that day. This is great if you mainly use your phone to receive calls and make the occasional call.
I would say the most generous plan would be Optus with their rollover of unused data a standout feature and unlimited calls and text with effectively 1 extra month of service over the course of a year compared to Vodafone and Telstra's plans. However, updates to the Amaysim deal recently put it ahead with their 2GB data per month unless you are likely to take advantage of Optus's rollover of data.