buying pennies

I was at the bank picking up pennies, and someone overheard me at the teller.
he says to me i have got some pennies which i have saved up over the last 15 years, do you want to buy them (assume at face value) since he was wondering how to get rid of them.
he says he has about a gallon of pennies, which seems low for the amount of time he has socked them away.
question is what should i pay. i am thinking of buying them by weight.
any recommendations. i don't have a real scale to weight them either.
thoughts?
he says to me i have got some pennies which i have saved up over the last 15 years, do you want to buy them (assume at face value) since he was wondering how to get rid of them.
he says he has about a gallon of pennies, which seems low for the amount of time he has socked them away.
question is what should i pay. i am thinking of buying them by weight.
any recommendations. i don't have a real scale to weight them either.
thoughts?