Acheron skins are a family of skins in CS:GO which currently only has one member which is AWP | Acheron. The skin was added to the game during the FACEIT 2018 - Ways to Watch update and is a part of The 2018 Nuke Collection. Acheron skins feature a multicolored hydrographic pattern on its side and can come in all five different exteriors, with each of them being available as a souvenir.
In terms of value, the price of it can range between a couple of dollars and $250 depending on the exterior as well as whether the skin is a souvenir.
Check out other CS:GO skins families: