Fees can be based on working days:
A daily rate for consulting can be agreed upon.
Fees will be calculated based on the number of days spent on the project.

Project fees can be a lump-sum:
Fixed lump-sum fee for a project can be agreed upon.

Consulting fees can be based on performance:
Performance fees can be considered with base fees and/or share of ownership.

Monthly subscription can be charged:
Direct expenses and VAT are not included in the fees.