I remember back in the old days, 3p gambling sites used to have 0 verification. You could deposit skins, each with their own attached real life value, to gamble for other skins. That way those sites could make double the money by fixing the prices skin had, and by gambling mechanics, without even needing a credit card

You can start by selling in Steam items from other loot boxes to buy more loot boxes. As well purchase steam gift cards to put money in your account.

They do actually

Maybe not a US thing but it’s very common in the EU