So im guessing your steam items skins which you wanna bet gets converted into coins.
What are 'skins'? Can I buy them with the $5 in my account? Or do I have to buy and play a steam game first, and somehow find the skins in-game?
As what NLNico said, can be traded, bought or received via in game. Some skins cost extremely high. Have a look at
https://opskins.com