The reason for the difference in value is that the copper-plated steel cents were produced in error. The United States Mint had planned to produce steel pennies in 1943 due to a shortage of copper, but they accidentally plated some of the steel cents with copper instead of zinc. The copper-plated steel cents were released into circulation, but they were quickly recalled when the Mint realized its mistake.
As a result of the error, the copper-plated steel cents are now considered to be rare and valuable coins. They are especially sought-after by coin collectors, who are willing to pay a high price for them.