the prices drop.
Monopoly is characterized by a regime in which only one firm provides the good or service to the population. In this way, the price charged becomes high, since there is no competition.
When the market opens to other suppliers, the company has to compete for the market and this competition happens for the price or the differentiation of the product. If the products are the same and the company charges expensive, it will lose all market share to competitors who charge a lower price. Soon, the entrance of the competition decreases the price.
