It seems also that Vodafone prepay only have $19 plans. Telecom at least has a $9 monthly plan and their $19 and $29 ones.
Low users seems more received with 2D and Skinny. Ie 2D's $8 chat pack and their standard $19 combo's and Skinny's $16 combo, text packs and their weekly plans. It makes sense that if you are going to make a phonecall for a few minutes to order a $4/week pack just before you dial out ... :D