Yes, divination cards, but LE style.
Here’s what I think COULD work:
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Cards are found and can either a) be used by the player, b) sold unopened to a trader or c) sold opened to a trader
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Players can also buy opened or unopened cards from the same NPC trader, in stacks or single
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Market price of unopened cards is determined in the background via supply / demand (practically it could be a formula of "people in game in the last 72h vs number of unopened cards available on the market, floating window is also possible)
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Market price of opened cards is determined by suppy alone (to give it a little twist) - meaning that only the number of cards put on the market, not the number bought, is setting the price
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Opened cards not sold are turned back into unopened cards after 168h or so