according to the comments below,
Elizabth St store doesn't have stock any longer, you might want to ring your local store to check.
according to the SN of my device, it was produced in the 38th week of year 2011, which is not too bad. battery lasts 1day for me at normal use.
I believe this phone is covered by 2 years' warranty from the purchase date (http://www.cultofmac.com/220083/apple-extends-australian-war...)
For the ones who bought the same device, suggest you to backup SHSH first so that you can downgrade the firmware later if you want.
I didn't backup SHSH, so now I can't downgrade from 6.13 back to 4.3.3(the original firmware came with the device)
on Tuesday, happened to see this deal on the counter in officeworks store on Elizabeth St store.
It's said to be locked to vodafone, but I unlocked it via below link for free:
Brand New.Came with a Vodafone prepaid sim card(free).
Upgrade it to IOS 6.13 via itune.
8G storage space might not be enough for nowadays, but good price to have it as a backup phone.
Paid with ING card, so actual price was down to $94.05
When I bought it, they had a few stock left.
Had issue with my computer, just fixed it today, sorry for sharing it late,
but I would suggest you to ring them first to check if they have stock now.
(no url online, in store only i think)