The iPhone 3GS is being given away for free by Best Buy in an offer valid only on Monday.

The deal is to renew the existing contract with AT&T or take fresh two-year contracts. As of now the iPhone 3GS is being offered at $50 to customers having the AT&T contract. So the customer will be saving $50.

The question here is whether it is worth buying the iPhone 3GS even though it is for free. The 3GS was launched in 2009. This means that it is already two years old and when you are taking the contract for another two years with AT&T you will eventually be using a four-year-old mobile technology.

The iPhone 3GS does have some good features. It has a 3 megapixel camera and a good battery life. It has a capacitive touch-screen with the design for bare finger or multiple fingers for multi-touch sensing. It also has the exclusive compass application for showing directions. But its memory is not expandable. Also unlike iPhone4, it does not have the un-insulated stainless steel frame that acts as the antenna of the device.

Apple is rumored to be launching the iPhone 5 in a matter of weeks. Apple will continue its support for the iPhone 3GS, but it is doubtful if this support will be effective for long. By all means there is the possibility that iPhone 3GS will be abandoned by Apple by next year.