Suppose you went to a farmers' market and found several different farmers selling cucumbers. Would you be likely to find a wide range of prices for cucumbers? Why/why not?

It depends on the market acumen of the farmers present at the market.

You would most likely find farmers selling cucumbers for about the same price. This would likely emerge as farmers would see what other farmers were selling the cucumbers for and would work to meet the price or get a lower price to encourage buyers to purchase their product.