A roll of US pennies that were all made after 1982 would weigh approximately 125grams. There are 50 pennies in a roll and each penny weighs approximately 2.5 grams. You can find more information here: www.parkpennies.com
The current United States penny, that is those minted since 1982, weighs 2.5 grams each. There are fifty pennies in a roll of pennies, therefore the entire roll would weigh 125 grams, or just a little over 4 ounces.