If you’ve been holding out on upgrading to an iPhone 4, this might sway you. Radio Shack has dropped $50 off the handset’s price tag. So you’re looking at a 16GB iPhone 4 (on contract) for $150 and a 32GB model for $250 (also on contract). This is pretty much the best deal being offered on the iPhone 4 by a major retailer. However, if that’s not enough for you, the Shack also has a slick trade-in deal going on. Your old 3G carries a value of $75 store credit, and your 3GS will earn you $125. So you can walk out of the store with a new iPhone 4 for $25, not bad! If this is still too rich for your blood, or you don’t have an old iPhone to trade, there’s one more sale option. If you’re not ready to take the plunge, you can score an 8GB 3GS for $50. We’re not psychic, but if you’re planing on picking up an iPhone we see Radio Shack in your future.