The best answer:
Ignore it and stand firm. Requests for a better discount, especially if you are already almost closing the sale, are simply attempts to achieve "the best deal possible." If you lower your price at this time, you will lose credibility and end up finalizing a business deal with very little profit.
How I can sell more? Why aren’t customers buying from me? Am I losing out?
Any entrepreneur or executive needs to perform permanent and constructive self-criticism by asking questions such as "How I can produce and / or sell more? Why aren’t customers buying from me? Am I losing out ? ", so says Juan Vega Gonzales, director of PROMIFIN, a program sponsored by the Swiss Cooperation in Central America.