Some points to take into account:
1) Only using 1-2GB/month
2) Don't really care too much about speed
Thinking it'll probably be Xnet River HSI Pay Per Meg especially as I can get a $50 for a friend referral (think they still do those...). Been to nzconnection.net (looks like it might need updating as it still mentions Xnet's Stream plan, which doesn't feature on Xnet's website currently).