What is the ruling on a man selling his car to a showroom and then buying it back from them in installments through the bank at a higher price?

The transaction mentioned in the question is not permissible because it involves a circumvention of riba (usury/interest). The sale of the car to the dealership is intended solely to obtain cash by interposing this commodity in a fictitious sale. The client then returns those funds to the bank with an increase for deferred payment, which is a circumvention to borrow with interest. Sheikh al-Islam Ibn Taymiyyah emphasized that any transaction whose purpose is to exchange money for money on a deferred basis is riba. Sheikh Yusuf Al-Shubaili pointed out that one of the conditions for Murabaha financing is that its purpose should not be to circumvent riba, and circumvention becomes apparent when the party ordering the purchase is the same as the seller to the bank.