sharing my view...
I am currently using virgin $29 plan. I was not able to use all the free call/credits since I am not a heavy users.
Why not able to consume data/credits on $29 plan?
If you already have internet at home, connect your phone to internet/wifi
If you and members of the family are with Virgin, its free call between virgin-to-virgin.
If I am in the office, you may use company office phone to call locally.
Before I leave the home to office, i try to browse facebook and download email on my phone so I can read it offline while travelling to the office.
going home, there are free MX newspaper to read on the train that keeps me pre-occupied.
After my contract finished, I plan to switch to pre-paid (amaysim or Aldi). Get the lowest mothly recharge or maybe get a 365 days pre-paid plan and reload when needed.
If I need a new phone, there are mobile phone that you can buy outright. Wait for sale or special offers. Look at jbhifi or Kogan for special offer. You can also ask for price matching.
Get the plan that you can afford.
Decide if you want a new phone and the kind of phone that meets your needs.
If someone can suggest a better way of savings for low user like me - much appreciated :-)