Called MrSimCard.com who I've seen recommended in other FT threads and was recommended to get a "Simple" sim card (uses t-mobile) which is $72 for Sim and first month of service and then $40/month (I'll be in the US for 2 months).

No data but unlimited international txts and unlimited minutes (including receiving international calls for no additional charges).

Seems like this is best option for me as I will get at least 30 mins calls per day from New Zealand and due to time difference would be good to be able to receive these while out and about.

Their customer service guy was very good. Patient with me in helping me compare some different options.

Main annoying thing is that I'll have to get a new SIM for next trip.