Ref. No. 2024/44-1994
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
If you have already made an agreement with a shopkeeper that the customer who goes to the shop in your name or with your slip, the shopkeeper will have to pay 5% commission on his total bill without any extra charge to the customer. Now, if the shopkeeper gives the goods to the customer at the market price, and the shopkeeper does not increase the price due to the workman, then it is permissible to take a specified commission from the shopkeeper. You go with the customer or send him alone to the specified shop, in both cases you are entitled to receive your commission.
لو سعی الدلال بينهما وباع المالک بنفسه ینظر إلی المعرف إن کانت الدلالة علی البائع فعليه وإن کانت علی المشتري فعليه وإن کانت عليهما فعليهما. (شرح منظومة ابن وهبان: ۲/۷۸)
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband