How to include fixed costs?

[quimetal]

Hi everyone;

 

I am creating an online store to sell invitations and other products. I need to include fixed costs of printing the invitation cards regardless of the number of cards purchased. Here's an example:

 

100 Green Invitation Cards * 1 € / unit = 100 €

I.V.A. 18% 18 €

Total 118 €

Printing costs € 40

Grand Total € 158

 

another example:

 

100 Green Invitation Cards * 1 € / unit = 100 €

Invitation Cards Yellow 75 * 2 € / unit = 150 €

I.V.A. 18% 45 €

Total 295 €

Printing costs € 80 (due to two types of cards)

Grand Total = 375 €

 

If you buy products that are not invitation cards (example: cups) printing costs do not apply.

Thank you very much for taking my request.