How can I create a pricing engine with a set fee for the first item and a different per item fee for each additional item?

I need a pricing engine in which 1 unit will be $13 and any quantity above 1 will be $0.05 each + the $13 minimum charge.  For example: 

 

1 Unit: $13.00
2 Units: $13.05
5 Units: $13.20
100Units: $17.95

 

You would create a pricing calculator.  You would have a single quantity parameter where the user could enter the desired quantity.  You would then have two hidden calculator parameters with the same parameter set name.  You would set them up as follows:

Parameter 1:
Name = Quantity

Option = Leave this field blank

Show As Option = No

Billing Type = Single Unit

Set up = $0

Cost Per Billing Unit = $13.00

Min Qty = 0

Max Qty = 1

 

Parameter 2

Name = Quantity
Option = Leave this field blank
Show As Option = No
Billing Type = Single Unit
Set up = $12.95
Cost Per Billing Unit= $.05
Min Qty = 2
Max Qty = some very large number that your customer would likely never order

 

Related Article: Ch. 013. Creating a Pricing Calculator Pricing Engine