Spark Trio SIM $1, Skinny Trio SIM $1, Spark Nokia 3310 $69 @ Smiths City

Spark Trio SIM

Skinny Trio SIM

Ok, not as cheap as it is in Australia*, but if your old man/woman needs a dumbphone in their lives then it could be helpful to give them a Nokia 3310 3G.

Month long standby battery life.

Makes calls and texts

Snake

This is the 3G model (Spark has no 2G) locked to Spark.

*You'll need to unlock the Australian Vodafone 3310 before using it in NZ. Locked means it wouldn't work with Vodafone NZ (but you can roam to VodaNZ without unlock). However, you could buy Vodafone AU Nokia 3310s and use them for spare batteries ;).