Buying a car on finance and then reselling it for a profit can be permissible in Islam, as long as the resale transaction does not involve interest (riba) or any other prohibited elements. If you are buying a car on Islamic financing, such as Murabaha, the resale should be conducted in compliance with the principles of Islamic trade. It is advisable to consult with an Islamic scholar or a qualified Islamic finance professional to ensure that the resale transaction is halal.