Protecting Your Integrity

You have just established a relationship with a person who is the contact at your newest customer.  Your customer makes the following statement to you before the first transaction takes place.  I expect for you to give me the best price you can possibly give me when ever I ask you to quote something.  In your effort to make a great impression you answer that you will ALWAYS do that and they can rest easy in the knowledge you will be a person of your word.  So things go along well for several months and then one day your customer comes back to you after you have quoted them a price and says something to the effect of:  can you do any better?  You give into temptation and ask how much better do I need to do.  They say 1000$ and the business is yours.  You say OK and you get the biz.
So the fact that you promised (remember they promised nothing but rather told you what was expected) to ALWAYS give them the best price out of the chute, pretty much goes out the window of greed vs. integrity.  If you gave them the best price where did that extra 1000$ come from?
Stand firm on your promises and if challenged that would be the time to play your value to them card not the concession card. When they say cut it 1000$ and the business is yours, you can say back to them, I cannot do that as I promised you to give you our very best price when we started and I did that so there is nothing left to give up.
You have no control over your competition or any of the other hundreds of variables that control pricing.  You do have control over your integrity.  Do what you say you are going to do when you say you are going to do it and you will be better served in your career and your life as well.