It's pretty hard to find a deal on an iPhone; they don't exactly pop up in the penny ads on Amazon like some Android models. If you've been wanting to trade your older model iPhone in for a shiny new iPhone 4, Radio Shack may just have your hookup.

Radio Shack is running a deal where they are cutting the price of all iPhone 4 models by $50, but that's not all. If you have an iPhone 3GS, you can trade it in for $125 in credit, knocking the price on a 16GB iPhone 4 down to a cool $25 after the stacked discounts. The iPhone 3G can be traded in for $75 in credit as well. The 32GB iPhone 4 runs $100 more like usual. The $50 off promo is only good until Saturday, so jump now if you're looking to step up.