The U.S. Mint spends 1.8 cents producing a single penny, worth 1 cent. Making millions upon millions of pennies per year costs the nation more in debt than it provides. Foreign nations have abolished the equivalent of the penny, rounded transactions to the nearest $.05, and not suffered any loss or inflation.
Pennies waste time for local shoppers, and this time amounts to almost $.06/transaction in labor/employee wages. Any transaction uses no more than 4 pennies, making the total cost for 4 pennies $.13 to produce and use. This makes each penny's production cost a grand total of $.033, three times as much as its own value.
Furthermore, pennies used to have value and be able to make purchases, but in today's economy, even the dime cannot buy as many items as the penny would 50 years ago.