American retailers face intense competition to offer consumer goods at the lowest possible price. while this saves consumers money, what side effect could damage our economy?

The correct option is this: TO OFFER PRODUCTS AT LOWER PRICES, MANUFACTURERS MOVE THEIR PLANTS TO FOREIGN COUNTRIES WHERE LABOUR IS CHEAP LEAVING AMERICANS OUT OF A JOB.
The major reason for operating a business is to make profits. No matter the prices at which products are sold in the market, manufacturers usually ensure that they make some profits because that is the only way they can remain in business. Thus, in a situation where the prices of product is very low, manufacturers will look for means of cutting costs so that they can make some profits. That is why a company will prefer to move to a place where it can get cheaper labor for its products.

The variety of games would increase due to competition, and the winnings per dollar spent would decrease.