بسم اللہ الرحمٰن الرحیم

الجواب  وباللہ  التوفیق

If the price is less if paid in cash while the price is higher in the case of loan, then this method is allowed in Shariah.  But the condition in this is that the nature of the contract should be decided from the beginning whether the transaction will be cash or loan and its price will be so and so in each case.  For example, a car if purchased in cash will be 10 lakhs and if through loan (in installments) will be for 12 lakhs. Now, if we decide to pay in monthly installments rather than cash, that will be allowed.  

However, if interest will apply for any delay in monthly payments, or if the total price of the car will decrease in case of early payment, then that becomes a usurious deal, which is not permissible. In general, the problem in buying products through loans end up in usurious transactions, which are not permissible. The only legitimate form remains the one mentioned above. If the selling company or a third party deals per those principles, it will be permissible to buy, otherwise not. 

اما الائمۃ الاربعۃ وجمھور الفقھا المحدثین فقد اجازوا البیع المؤجل باکثر من سعر النقد بشرط ان یبین  العاقدان  بانہ بیع مؤجل  باجل معلوم و بثمن  معلوم متفق علیہ عندا لعقد .... بحوث فی قضایا فقھیہ معاصرۃ  (احکام البیع بالتقسیط :۱۶؍۱۵۵) فتاویٰ محمودیہ

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