Skype (via Acer UK Facebook page) is offering 1 month of free calls by simply registering your email address. As stated on the site, you will receive an email with a voucher code within 24 hours.
Seems very straight forward, and available to New Zealand.
Full T&Cs are available here.
Voucher looks like this. Apparently, it takes up to a day to receive the credit. You have until March 1 to activate the unlimited plan so good if you have a holiday coming up.
Credit to AU Tightarse from OzBargain