The Market Game is a memory game. Players alternate and needs to remember what they had in their imaginary market list. You first tell the first item you bought. Then Alexa repeats your item and on of hers. Then you repeat your first item, Alexa's first item, and your second item. And so on.
In practice: you start with an item, e.g. "Today, I went to the market, and I got chicken", then Alexa will repeat your item and will give you another (e.g. lemon). Then you repeat your first item, then Alexa's item, then you propose a third one, etc., e.g. "Today, I went to the market, and I got chicken and lemon and ketchup". NOTE: Food items work better. Also make sure to add an "AND" between each item.
Another example on round two: "I went to the market, and I got beef, and, coffee, and tuna."