Some nice deals on Jetstar Friday Frenzy:
Sydney to Christchurch $119
Melblourne to Christcurch $139 and so on
Trans-Tasman Routes
Sydney - Christchurch: 21 Aug - 18 Sep, 15 Oct - 4 Dec 2013, 5 Feb - 9 Apr, 6 - 20 May 2014
Melbourne (Tullamarine) - Christchurch: 4 - 18 Sep, 15 Oct - 4 Dec 2013, 5 Feb - 2 Apr, 6 - 20 May 2014
Melbourne (Tullamarine) - Auckland: 30 Jul - 18 Sep, 15 Oct - 4 Dec 2013, 5 Feb - 2 Apr, 6 - 20 May 2014
Gold Coast - Auckland: 3 Sep - 17 Sep, 15 Oct - 4 Dec 2013, 5 Feb - 2 Apr, 7 - 20 May 2014
Sydney - Queenstown: 23 Aug - 16 Sep, 18 Oct - 9 Dec 2013, 3 Feb - 4 Apr, 9 - 19 May 2014
Sale fares do not include checked baggage^. You can add baggage for a fee, for example 15kg - 40kg checked baggage can be added for an additional $25 - $60 per passenger, per trans-Tasman fare.
Also, they have Melbourne to Hobart at $39 one way in Aussie Escape Sale
and for an extra cost, they now allow you to pay a surcharge for either a smooth take off or smooth landing (but not both)