You know the Contractor's Triangle? You can get a job done fast, well, and cheap, but you can only choose two out of three. That's been the rule with cell phones, too: They can be powerful, pretty, and/or inexpensive. Pantech's new smartphone, the Discover, attempts to deliver on all three. It has a 4.8-inch screen, a 12.6-megapixel camera, a 1.5GHz dual-core processor running Android, and it operates on fast LTE networks (starting with AT&T (T) on Jan. 11). With a two-year contract, it will cost $50.