The fastest and easiest way to get clothing and weapon skins is to buy crates through the in-game store with their currency. The game does however provide you with a free crate every five levels, level fifty is a bronze crate which provides reasonable chance for rare items and level seventyfive and hundred are for Silver and Gold crates which gives high chances and definite chances at Ultra rare items like gun camos and the helmet skins. High round placing in game events will also enable you to win crates but to enter these events costs hundred gold coins. Skins do not affect your stats, and are only there for visuals and aesthetic.