Here is a list of all the skins in the game pretty much, including the unlockable ones. Not mentioned are the Liquid Metal Lancer which you get with the purchase of the Season Pass. The bottom 22 skins though, are attainable by purchasing them on Xbox Live on Day 1 of release (September 20th). I’m thinking maybe 800 Microsoft Points for all those bottom skins but hopefully it more like 120 Microsoft Points since they are just weapon skins!
Gold Onyx Skin Attained by Reaching the Highest Level in Multiplayer
Unlocks:
Chrome
Gold
Gold Omen
Crimson Omen- Hammerburst/Retro/Gnasher/SOS from doing things in-game.
Flame
Team Insignia
Onyx
DLC:
Infected Omen
Liquid Metal
Liquid Green
Paid:
Garish
Artic Camo
Desert Digital
Desert Camo
Deadly Cute
Childs Play
Blood
Electric
Flower
Haze
Imulsion
Rainbow
Team Pulse
Oil Slick
Ocean
Thunderstorm
Team Distress
Team Metal
Tiger Stripe
Jungle Digital
Tribal
Urban Digital