To find yourself in an economy is to find yourself in uncertain thicket. Thickets beyond full, perhaps beyond, real understanding. Perhaps because there is no organic nor atomic basis for the economy. See these notes:

Theory of Value: an axiomatic analysis of economic equilibrium: note (p.28) “… it is assumed that the economy works without the help of a good serving as medium of exchange.” — Debreu

but Herr Docktor knows it is odd to define away money from an analysis of economic value. He offers further self critical awareness to us with this item:

Two important and difficult questions are not answered by the approach taken here: the integration of money in the theory of value.. and the inclusion of indivisible commodites. — page 36, Theory Of Value

Now you know more about the card game, do you feel better about the price of knowledge?