You will never get a better price unless you ask for it. Most buyers don't ask because they don't like rejection, but rest assured if you don't ask, they won't offer. If you want to realize appreciable savings that could improve your company's bottom line, you must have the courage to ask. However, asking by itself is not sufficient. You must also know how and what to ask for.
Timing is everything.
If they insist they don't have the authority to drop the price, don't stop there. If you continue to test them and they still hold firm, then be prepared to walk out, telling them you will have to look elsewhere. However, if you do this, consider walking back in at a later date and staring all over again, either with the same salesperson or another one. The best way to succeed is to look for a win-win agreement rather than a straight price negotiation. If the quantities on that order can still be changed, it will cost the seller nothing to honor your request.