[shoo]

The decision depends upon what value I think the t-shirt has, what value I think the money token has, what value you think the t-shirt has, and what value you think the money token has.

I guess I am thinking of money as being a token of favour against a third party (<government>) not involved in the transaction, and moreover being a token for a favour that will never be invoked.

edit: From this perspective it seems reasonable to ask "what difference does it make what the third-party is?" and "if the favour is never to be invoked, why think of it as a favour at all?".

edit 2: the "favour" and the "value" here are quite different ideas, if that part is confusing.