Final answer:
Spot buying is the buying at market prices determined by supply and demand from someone that the consumer does not know.
Step-by-step explanation:
The buying at market prices determined by supply and demand from someone that the consumer does not know is called spot buying.
Spot buying refers to purchasing goods or services at the current market price, without any prior contracts or negotiations. It is a one-time purchase from an unknown seller based on the existing supply and demand conditions.
For example, if a consumer needs to buy a specific product urgently and finds a seller offering it at market prices, without any long-term contract or negotiation, it would be considered a spot buying transaction.