Why are you asking the customer what they think is a fair price? If you've done your research, you know if you're charging a fair price or not. If you're not, make adjustments or figure out a way to justify why they should pay *you* more for the same service. If you are then you tell the ahole "This is the price I charge for that service. If you want to give me less money, you'll also be receiving a lesser amount/quality of service and we need to determine where the cuts will be made." If they want to argue about it, wish them "Godspeed" and tell them you will follow their future endeavours with great interest.