What% to give to the manager?

Question

Project management

Let's say I hire a salesperson who will look for projects for me to develop. What% of the sum to give him so that he was pleased and I.

Answer 1

10-20%
I would give a percentage of the amount.
Finds a project for 30t.r. you give him 10%, he finds a project for 500t.r. give him 20%.
There will be an incentive to look for more expensive projects for you