Counter-Strike: Global Offensive (CS:GO) weapon skin, trade-up contract, ten skins of the same quality, one skin of higher quality, random weapon, collection, exterior condition, probability, market value, gaming, first-person shooter, inventory management, Steam platform, Valve Corporation, eSports, in-game economy, virtual goods, cosmetic items, rarity levels, consumer grade to covert, skin float value, wear rating, game mechanics, strategic planning.