I have had a request for a wholesale order of my cake sandwiches. They are only wanting the shells (the cake part) with no filling. I usually charge $18/dozen which is actually 24 shells. So how do I figure what I should charge for 600 individual shells. She is saying she might want to order up to 2400 of them but wants to start with 600. Any help would be appreciated!

Thanks!
Stacey