Amazon's resellers are selling the HTC One unlocked for whopping $799. T-Mobile's HTC One will be released on April 19, too. It can't be pre-ordered, but we know it's going to cost $99 upfront with $20 per month for two years. AT&T and Sprint are both asking $199.99 on contract. So unless you must have the Unlocked version, i wouldn't recommend it.
HTC will also introduce a Developer Edition of the One on April 19. This comes with 64GB of internal memory, unlocked SIM and unlocked bootloader, and will cost $649. You should get that instead.
HTC One is the Taiwanese company's flagship smartphone for 2013, offering lots of high-end features, including a 4.7 inch Full HD display, LTE, quad-core 1.7GHz processor, and a 4MP Ultrapixel camera.