Whether it is permissible to take a discount for paying by debit card depends on who is giving the discount. The details are as follows:
If the discount is given by the bank, it is not permissible according to Shariah to take it. The cardholder receives this discount because of their bank account, and according to Shariah, money held in a bank account counts as a loan to the bank. Any benefit received because of a loan falls under riba (interest).
If the discount is given by the business where the purchase is made or the meal is eaten, it is permissible, because it is a voluntary gift and kindness from that business.
If the discount is given jointly by the bank and the business where the purchase is made, the part given by the bank is not permissible.
If the discount is given by neither the bank nor the business, but by the company that issues the debit card, it may be used, provided that all or most of that company’s dealings are permissible and all, or at least most, of its income is halal.
If it is not known who is giving the discount, it should be avoided.
Please note that this ruling applies to debit cards issued by interest-based banks. The same ruling also applies to current account holders of interest-based banks.
The dealings of interest-free banks, on the other hand, are supervised by qualified muftis, who ensure that Shariah principles are followed before such discounts are allowed. Relying on these scholars, there is room for both current account holders and debit card holders of interest-free banks to use the discounts these banks offer.
Taken from Fatawa Banuri Town, Fatwa No: 144106201014
Allah the Almighty knows best.
Darul Ifta Al-Ikhlas, Karachi.