Startup costs / pricing per design

Like to start with FPD for our co2 laser burning company and explore the options . 

count not find a option to set a setup price for each design. 

for example, A burnt tray would be like 5 euro each. 
but to start producing we have startup costs (for each design) of 15 euro. 

so 1 items would be 20 euro. 
2 would be 25 euro 
3 items 30euro

above 10 pieces the price each items could drop to 4 euro. 

how could I accomplice this with FPD 
I only see options for text lenght and adding images etc. 
but not for the ammount of each design a customer orders.