penny-n; 2 Senses

Sense Number 1: one hundredth of a base unit of currency

Commentary: PENNY[+artifact][+currency][+coin][+copper] [+quantity][+currency][+unit][+portion][+hundredth]
NOTE: emphasis is on the actual coin, or its unit value as a currency

There are one hundred pennies in a US dollar.
John found a lucky penny in the street.
You can probably not buy anything nowadays with just a single penny.
The child put pennies, dimes and nickels into his piggy bank.

WordNet 3.0 Sense Numbers: 1, 2

Sense Number 2: an unspecified sum of money

Commentary: PENNY[+quantity][+sum][-specified][+high/+low]
NOTE: refers to a vague sum of money, not the unit of the currency.

Bob's Porsche must have cost him a pretty penny.
I won't give another penny to that organization after what they did.
You wind up spending a penny here, a penny there, so it does start to add up.
For only pennies a day, you could provide food and medicine to a needy child.

WordNet 0.0 Sense Numbers: 5