Cost of paper for the final print,
Cost of paper for proofs/test prints,
Cost of Developer, Stop, Fixer, toning,
Cost to develop film,
Cost of your time,
Cost for the use of your Equipment (cameras, darkroom, lighting, etc),
Cost of the studio/space/location...
This sound a bit high end. If it was me, I would have a frank and earnest discussion of what your price would be and what the "client" would receive in return. Putting it all in writing (a contract) would be a good idea.