Giving the representative money to buy from him
Question

                I have a customer who buys goods from me and he is the representative of a company. I sell him the goods on the basis that if he finds these goods for a lower price, he will return the goods to me or I will give him a discount, but if my price is the same as the market price then I should be the first choice for him to buy from me, on the basis that I will give him some money and he will not include it in his accounts with the company owner. Please advise me, may Allaah reward you.
Praise be to Allah.
    It is not permissible to give the representative any money or 
    gifts, because that comes under the heading of bribery and haraam gifts to 
    workers. He is employed by his company and buying the goods is part of his 
    work for which he is paid a salary; he is acting on behalf of his company 
    when he makes purchases, and any profit or discount that he gets should go 
    back to the company, and it is not permissible for him to take anything of 
    it. 

    Ahmad and al-Bayhaqi narrated that the Prophet (blessings and 
    peace of Allaah be upon him) said: “Gifts to workers are ghulool (lit. 
    stolen war booty),” meaning a betrayal. The hadeeth was classed as saheeh by 
    al-Albaani in Saheeh al-Jaami’, no. 7021. 

    “Workers” means employees, so everything that comes to the 
    employee because of his work is a kind of betrayal and haraam. 

    Al-Bukhaari (7174) and Muslim (1832) narrated that Humayd 
    al-Saa’idi (may Allaah be pleased with him) said: The Messenger of Allaah 
    (blessings and peace of Allaah be upon him) appointed a man from al-Asad who 
    was called Ibn al-Lutbiyyah. When he came he said: This is for you, and this 
    was given to me. The Messenger of Allaah (blessings and peace of Allaah be 
    upon him) stood up on the minbar and praised and glorified Allaah, and said: 
    “What is the matter with an agent whom I send, and he says, ‘This is for you 
    and this was given to me’? Why doesn’t he sit in the house of his father or 
    the house of his mother and see if he is given anything or not. By the One 
    in Whose hand is the soul of Muhammad, no one of you gets anything from it 
    (unlawfully), but he will bring it on the Day of Resurrection, carrying it 
    on his shoulders, even if it is a groaning camel, a lowing cow or a bleating 
    sheep.” Then he raised his arms until we saw the whiteness of his armpits, 
    then he said: “O Allaah, have I conveyed (the message)?”  three times. 

    It may be said here: if this representative sat in his house, 
    he would not be given anything; he is only being given something so that he 
    will buy from you for his company. This may make the employee betray the 
    trust, so he buys from the one who gives him things, even if that which 
    others have is better and more suitable. Hence sharee’ah closes this door. 
    So no gifts should be given to the worker, and nothing should be given to 
    him. 

    It is very unfortunate that these bribes are widespread 
    nowadays, and people have come up with various kinds of them, even adding to 
    them deceit and lies, so the seller writes a false price for the 
    representative, and a fabricated invoice, to help him betray the trust and 
    acquire haraam earnings, so that he will buy from him again. What we should 
    do is beware of all things that come under the heading of bribery and haraam 
    gifts for workers. 

    And Allaah knows best.