Jazzy from my understanding you still need a landline with most other providers. I don't need a landline I have a cellphone that does everything I need as DP is my bestmate so can call/txt/pxt him all I like and mum has me as her bestmate so she can call me when I need her. Everyone else I have enough minutes and txts to use.
I would need to look at naked broadband and from my understanding pretty much the only ones that do are snap, xnet, vodafone, and orcon
Actually I did just see that slingshot does but its expensive. There are low usage deals out there but I looked through them all when I first could get out of my contract with vodafone and they are just as expensive or just a little bit less then what I got at Vodafone.
For 10gb at Vodafone I would pay $55 for the same with slingshot or Orcon its $80+