Huntsman Fade Factory New is a Covert CS:GO skin that was introduced to CS:GO on May 1st, 2014 as a part of The Hunt Begins Update. The design of the knife features a chrome base coat with numerous transparent paints that fade together airbrushed over it. The Huntsman Knife Fade FN can be obtained as a random reward drop from the Huntsman Weapon Case, however, an appropriate key is required to open it.
The Huntsman Knife Fade is available in two different exteriors, them being Factory New and Minimal Wear, and has the ability to have StatTrak technology attached to it. As far as pricing goes, the regular versions in both exteriors can be obtained for around $250 with the Factory New version fetching a few dollars more. In a similar design, the StatTrak versions of the Huntsman Fade skin will end up costing you a bit over $400.
You don't need more sell skins for real money; on DMarket you can trade CSGO skins for other skins.