AT&T has announced an upgrade to its in-store smartphone trade-in program. The plan will give an instant credit of at least $100 for any smartphone that is less than three years old, with more recent and valuable phones receiving larger credits. The credits are good for the purchase any AT&T smartphone or accessories, meaning someone could trade in an older Android smartphone for a new iPhone 4S, or half-price on a 16GB iPhone 5. Beginning May 1, consumers who trade in their current smartphone to AT&T* will be eligible to receive at least $100 off the purchase of a new smartphone, including the new Samsung Galaxy® S 4, BlackBerry® Z10 or 32 GB HTC One®. These devices are normally $199.99 with a qualifying two-year agree
