A market in a dream can represent choices that you are faced with in real life.
Dreaming that you are in a large supermarket can be a sign that you have too many difficult choices to make and you are overwhelmed.
A dream that you are in an outdoor market can be a reminder that a situation you are in is not permanent.
Buying or selling something in a market in a dream can mean that you have to negotiate with someone. It can be a message that you need to compromise.
Dreaming about a market can be a sign that you need to look at the financial side of things or that you need to be more practical.
Items that you purchase in the market can represent things for which you have an emotional need. If you buy food, it can mean that you feel emotionally undernourished.
Things that you sell can symbolize thoughts or memories you no longer want.