If you bought an iPhone 3G when they came out in the UK in 2008, and now want to purchase the new iPhone 3GS it is going to be expensive.

Existing iPhone 3G owners who want to upgrade to the iPhone 3GS will have to buy themselves out of their existing O2 contract, assuming you purchased your iPhone 3G on the 11th of July 2008 (launch day), you will have to pay a minimum of £245 ($395), this is based on the cheapest iPhone 3G Plan of £35 per month.

Add to that the cost of the new iPhone 3GS which is £185.98 ($300) for the 16GB version and £274.23 ($442), this means that to upgrade to a 16GB iPhone from the iPhone 3G it will cost you a total of £430.98 ($695) and to upgrade to the 32GB version it will cost you a total of £519.23 ($817).

Please note the above figures are based on users who purchased the iPhone 3G on launch day in the UK and are on the cheapest iPhone contract.

When the 3G iPhone came out, users were allowed to upgrade from the 2G iPhone without any additional cost, all they had to do was sign a new 18 month contract.

I asked O2 why the aren’t offering this option to existing iPhone 3G owners this time, the reason behind it is that the iPhone 3G and iPhone 3GS are heavily subsidised by O2 where as the 2G iPhone wasn’t.

To be honest this sucks for existing iPhone 3G, and I think Apple and O2 have really missed a trick here, as the majority of people who would want to purchase the new iPhone 3GS would be existing iPhone 3G owners.

If I had been able to upgrade to the new iPhone 3GS without an additional fee I would have purchased the 32GB on launch day and signed a new 18 month contract with O2, now I will have to wait until December before I can upgrade unless I want to pay an additional £245 on top of an already expensive iPhone 3GS.