Invoicing customer

[979starchief7]

I have a customer who bought 3 figurines from me and we bargained back and forth and came up with a price of $55 for all 3 but that price would include shipping. How do I go about putting together an invoice to send her that reflects that price? By the way, at that price at least one of the items will have to be discounted from what the listing price was. This is my first time having a situation like this and I am sort of clueless as to how to go about it. Do I need to attach the listings for you to know what I am talking about?

Thanks