Apple iPhone

Apple iPhoneYou may have shelled out up to $599 for an iPhone (if you live in the US, that is). And you may have had to sign up to a two-year AT&T contract. But it seems that won't be the last of your costs if the battery starts to fade on your iPhone.

Like Apple's iPod, the iPhone has a fixed battery that can't be removed by users.

So if it starts to die and needs replacing, that could cost you more than $100.

Let us break it down for you:
* It costs $79.95 for official Apple technicians to pop the battery out and put a new one in.
* Which means you need to pay $6.95 to send it to them.
* And if you want to borrow a replacement iPhone while the work is carried out over three business days, that's another $29.

The arrangement is similar to the system used to replace failing batteries in iPods, which are also fixed within their casings.

Will users turn to unauthorised, cheaper repair methods, even though that will default the iPhone's warranty?

Possibly, says Gartner analyst Carolina Milanesi.

"As far as third party suppliers offering solutions I am sure they won't be put off, but as a consumer I would think twice before invalidating the warranty," Milanesi said.