T-Mobile USA is planning to launch smartphones priced at $100, around half of the usual cost, supported by currently-available $10-per-month data plans, according to the Wall Street Journal. This was seen as acknowledging that rivals AT&T and Verizon Wireless are already dominating the high-end market, with devices such as Apple’s iPhone, RIM’s BlackBerry Torch, and Droid devices from Motorola and HTC.