Add T-Mobile and Sprint to the list of carriers that have announced when they will start selling the widely anticipated Samsung Galaxy S 4. T-Mobile on Wednesday said it will let users order the device online starting April 24 and will sell the smartphone in some of its retail stores starting May 1. The 16-gigabyte version will cost $149.99 up front plus 24 monthly payments of $20, or a total of $629.99. Sprint, meanwhile, will make the phone available for preorder online starting Thursday. The Overland Park, Kan., company will start selling the phone in stores April 27. Sprint said it will sell the 16-GB version of the GS4 for $249.99 with a two-year contract. The company also said it will offer users a $100 credit if they buy the GS4 and switch from another carrier. AT&T this week began taking preorders for the 16-GB Galaxy S 4 online for $200 with a two-year contract. The device won't ship until April 30. Verizon is the only major U.S. carrier that hasn't announced when it will sell its version of the phone. The GS4 features a 5-inch display, and has a better processor and rear camera than its predecessor, the Galaxy S III. Samsung also focused on improving the internals of the GS4 and giving it numerous new software features, including one feature that scrolls down Web pages by detecting the movement of the user's eyes. From the outside, the S 4 and the S III look quite similar. The new Samsung phone is launching shortly after the HTC One, setting off a sales duel between the two much-anticipated Android devices.