$60USD is around $70NZD, but bear in mind the US price excludes any sales tax (US companies always display prices exclusive of tax) so the 'true' Nz price would be $70NZd+GST, or around $80NZD
Now ok that is less than $99, but it's hardly a huge amount less.
However, I also think that your $99 seems on the high side.
If all you care about is data, then you can get a 3GB data pack from 2D, Telecom, or (I believe) VF for around $50-60NZD and forget the minutes. Most overseas carriers don't allow you to use standalone data packs on phones, but NZ ones do.
Compare that to NZ where on Vodafone you'll pay NZ$69 and get unlimited calling to NZ/AU, unlimited SMS and 1.5GB/2GB/2.5GB (depending on where you sign up for this deal)
Anyway this thread is now getting very off topic..