Depending on the carrier and which plan you use, the HTC One X ad the HTC One S can be had for free. For example, O2's On and On plan for £36 per month ($57 USD) offers unlimited minutes and a free HTC One X with a signed 2-year pact. A Sim-free, carrier agnostic unlocked version of either phone is available via Amazon. The HTC One X is priced at £489.99 ($780 USD) via Amazon and the HTC One S is £414.99 ($660 USD) from the online retailer, both without a signed contract.
The HTC One S has a smaller (but not small!) 4.3 inch Super AMOLED display weith qHD resolution and pixel density of 256 ppi. A dual core 1.2GHz Snapdragon S4 will be driving the phone with 1GB of RAM on board. With no microSD slot on the device, you are left with the 16GB of native storage that the HTC One S is equipped with. The rear facing 8MP camera captures video in 1080p at 29 fps, while you can take self-portraits and engage in video chats using the 1.3MP front-facing camera.
We might add that both models include Beats Audio technology.
source: TheVerge via Phandroid