Redbull Mobile is worth a look too is you want value, and ok rather Telstra's best 4g service.
It is on Vodafone's 3G netwok.
Prepaid Plans* - Red Bull MOBILE Australia
$365 for 15 months currently get you per month:
5GB data and
[TABLE="class: plans-table highlight-included, width: 100%"]
[TR]
[TD="class: desc"]Standard National & Mobile Calls[/TD]
[TD="class: pink upper, align: center"]Unlimited[/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[/TR]
[TR]
[TD="class: desc last"]Standard National SMS/MMS[/TD]
[TD="class: pink upper, align: center"]Unlimited[/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[/TR]
[TR="class: hilite, bgcolor: #F8F9FA"]
[TD="class: desc last"]13/1300 & 18/1800 calls
and Voicemail[/TD]
[TD="class: pink upper, align: center"]Unlimited[/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[TD="class: pink upper, align: center"][/TD]
[/TR]
[/TABLE]
Data is billed in 250kb sessions.
That is pretty good value for an average of $24.33 per month.
In my case this is for my teenage daughter, and a big plus for me...and her is that she does not have to worry about exceeding a monthly cap now, which on her old plan was an ongoing issue.
Boost would probably give a better service, but data is billed in 1MB sessions, with a 3GB cap and at a 15 month cost of $600.