Part of the reason for the underground market for tide is its liquidity. Not literal liquidity but fiscal liquidity. Everyone needs detergent; it is easy to negotiate with a black market dealer to take detergent instead of a full cash payment. I used to work at a certain retail store and there was a man who constantly got caught stealing tide. There was a police report written about how he was using it to barter payments to others for various illegal things. It is a very interesting way to launder money, so to speak.