Normally when I spot a cheap gaming-related deal or sale, I mention it to Mark and let him handle it. But since he's currently swanning around the US eating burgers and confusing people even more than usual with his impenetrable Scottish brogue, I guess I'll have to tell you about it myself.
Vodafone has the global lock on selling the Vita on a SIM contract, so it's not surprising that the Australian operation is using another familiar tactic: offering a free Vita when you sign up to a 24-month contract with its mobile phones. The plans cover Android phones from Samsung, HTC and Sony, and include the 3G version of the Vita, though without any extra credit for the device. But really, for the amount of data usage you're likely to need, prepaid should be fine.
By my reckoning, the Vita's not an appealing enough device to make this a reason to switch phones in its own right, but if you're tempted by one of the devices on offer anyway (the Nexus and the Sensation XL are the best phones in this lot) and haven't suffered a terminal case of "never again" from prior bad Vodafone experiences, it might be worth considering.