Looking to buy a new mobile and have only $50 bucks to splurge? Then don’t despair- you could walk away with a brand new iPhone 3GS with just those 50 bucks. RadioShack, the electronics retail giant, has slashed $50 off all iPhone handsets and is also offering trade-in incentives that could get you a brand new iPhone 4 for as little as $25.

The unprecedented sale designed to boost awareness of RadioShack’s wireless business and create an edge up on the competition, began Saturday morning and runs through December 11th. The discount means new and existing AT&T customers can take home an iPhone 3GS for as little as $50, a 16GB iPhone 4 for $150, or a 32GB iPhone 4 for $250.

In addition, RadioShack also offers a “Trade and Save” program for all users with a working older iPhone 3GS and iPhone 3G. A good quality iPhone 3GS will fetch a $125 credit toward a new iPhone, and a iPhone 3G will receive a $75 off. Credits are extended to customers in the form of RadioShack gift cards. Therefore, if you trade in your undamaged iPhone 3GS you will receive a $125 credit plus an additional $50 discount, so you can get a brand new 16 gigabyte iPhone 4 model for $25 instead of $199.

Or even better, a customer trading in an iPhone 3G ($75 credit) for a new iPhone 3GS ($50 during the sale) should be able to walk away with a new iPhone 3GS and $25 gift card at no cost! However, this program doesn’t apply on jailbroken and unlocked iPhone devices. The only restriction is that the deal is valid in RadioShack retail stores but not available online.