This is a costing for someone who asked:
Current Plan $18.99 per month with extra charges for going over the limit.
Buy the iPhone 4s 16Gb for $799
Total minimum cost over 24 months is $1,254 (for iPhone and current plan)
But this could be higher if the monthly cap is exceeded.
For example, if the monthly cap was exceeded by an average of $15.00 per month, then the total minimum cost over 24 months would be $1,614 , and the following Unlimited call plan would probably be better.
Option to change to new phone with Unlimited call plan
Vodafone Infinite gives almost Unlimited calls:
Infinite calls to anyone you want at home or on their mobile within Australia. Now there’s no need to have two separate phones for home & mobile.
infinite TXT to any personal mobiles here & overseas.
Text anyone here in Australia as well as to anyone overseas
The cost:
$50 pm for the Vodafone Infinite Business Plan
$17 pm for the iPhone 4s 16Gb
Total $67.00 per month
Total minimum cost over 24 months is $1,608