Wow! Black is more popular than White! I just realised they now sell the handset alone, now that’s more like it 
Bad News is you cannot go on Prepay according to Vodafone’s Q&A Section on the website.
Question: I am a Vodafone Prepay customers can I get iPhone 3G on Prepay
Answer: No, iPhone will not be available on Prepay.You need to have subscribed to either an iPhone plan or alternatively a standard On account plan (You Choose, talkZone, or Corporate) with a compatible Broadband plan for mobiles.
To purchase this product you must have “good” or better coverage in your area.
Check your iPhone coverage here http://www.vodafone.co.nz/help/coverage/index.jsp
