Definition:Halfpenny/Linguistic Note

Linguistic Note on Halfpenny
The usual plural of the word halfpenny is halfpence.

However, the word halfpennies would sometimes be used in rhetorical speech if it was required to emphasise the paltry quantity of the money in question:
 * I've only got a few halfpennies.

Note that halfpenny is pronounced hape-nee, and accordingly often spelt informally as ha'penny.

Similarly:
 * halfpennies is pronounced hape-nies, and often spelt informally as ha'pennies
 * halfpence is pronounced hay-pence, and often spelt informally as ha'pence.