Just a few short months after Virgin Mobile's Sprint-fueled US arm listed the iPhone 5 for sale, the MVNO is teasing the smartphone's successors as "coming soon." According to the firm's homepage, both the iPhone 5s and 5c will debut for prepaid customers, though pricing and availability remain unknown. Judging by the previous-gen's starting price of $550, however, you might want to start saving up now. The iPhone 4S, meanwhile, remains on the ticket. That handset is currently listed for 15 percent off its $450 sticker price, available today for $382.49.