How much to charge?

I did ask on the thread "Anyone else making things for Christmas fairs" but it sort of got overlooked sooo….

Please could anyone give me an idea of what to charge for knitted Ferrero Roche (sp?) hats - with the chocolates! I've made snowmen, puddings, robins and Father Christmas hats but have no clue as to what to ask for them. I've also done chocolate oranges with Christmas pudding covers. I've knitted what feels like millions and have had to be really firm with myself not to break into the chocolates and scoff them. I do go and sniff them regularly!
I'm hoping to help raise lots at a charity event on Dec 1st.
Thank you