First freelance job - How much should I get paid?

I'm an automotive engineering student. Last week I found a freelance job as a mechanical designer. I am asked to design on solidworks the bodywork of a 1:43 car model. This model will be an extremely fancy one, produced in few pieces and with extraordinary attention to details. For sale only to selected collectors. The price of a single piece could be near $4000. Every other part of the car will be designed by the owner of the business and nearly every part will be 3d printed by him. Since it's my first time designing something professionally, how much should I get paid for this job?