The poskim say that giving a good piece of advice is a mitzva from the Torah [it is both chesed and a fulfillment of the pasuk לפני עור לא תתן מכשול which teaches both that one may not mislead someone and on the positive side one should lead others on the right path]. So I am going to share. Do you want to hear? Is it OK if I share?? If you are not interested then stop here....
I just made a phone call to purchase an item I need and the man said "300 shekel". I innocently asked if he has for less money. 30 seconds later he gets back on the line and says that he asked his superior and he can give it to me for 260. So I potentially saved 40 shekel and it only cost me one little question and a 30 second wait.
Then I called up someone else for the same item. I knew how eager he was to keep me as a customer [and I am eager to buy from someone who is so eager to please] so I told him that the price he quoted was to high [it was]. He went down 70 shekel and is doing the delivery for free [last time I paid 80 shekel].
Moral of the story: Ask. If you are a good haggler - haggle.