Physical tokens of money and discussion of money and economics are considered vulgar and crass in this culture, yet there is a vast economic gulf between the very poor and the very rich. There is a large pressure to be able to maintain outward appearances at even great cost; otherwise, one would try to avoid being seen in 'cultured public' and to constrain their interactions to only other underworld lowest-class like themselves.
Just to be clear: there is money, and it's used often. Just not talked about or done 'in public'.
I imagine middle-class shopkeeping and merchandising professions would be looked upon with contempt and disgust, which would further divide the social classes. Additionally, little to no economic theory would be developed--again, reinforcing the current status quo.
However, what could the origins of this society be? What could some historical/cultural influences be which would cause this society to have developed?
E: a bit more information: Friendly 'gifting' (really a form of barter) plays a large part in day-to-day life. Commercial stores are typically built and placed to allow discreet entry and exit. Once purchased and paid for, the product will typically be delivered to the buyer's home address, where they will give a token gift to the deliverer, thus making it clear it's just another friendly exchange, nothing so dirty as a money-related transaction.
Many people do their own spending and moneykeeping--as much in the privacy of their own home as possible--but many more hire others, and rarely if ever learn the state of their own accounts.
But why could such a taboo develop?