I think CS:GO may become F2P soon
http://steamcommunity.com/market/listings/730/CSGO Weapon Case
Yeah, a handful of strings related to in-game purchases popped up earlier in the year:
"StoreUpdate_Loading" "Loading the Store..."
"StoreUpdate_NoGCResponse" "The Store is currently closed."
"StoreUpdate_NewPriceSheetLoaded" "The product list has been updated to the latest version."
"StoreUpdate_ContactSupport" "Please contact customer support to have your Steam wallet configured."
"StoreUpdate_OverlayRequired" "You must enable the Steam Community in-game and restart the game to use the Store."
"StoreUpdate_SteamRequired" "A connection to Steam is required to use the Store."