Substituting old commodities with new ones for some money

Q 1: We have a place where household appliances are exchanged, so you can exchange an old refrigerator or washing machine for new ones and pay the difference in price. What is the ruling on this? (Part No. 13; Page No. 166

A: There is no wrong in exchanging old household appliances for new ones along with an increment paid by the owner of the old appliances due to the difference between the value of both types. This is a sale that Allah (Exalted be He) has made lawful, and it involves no prohibition. This is so, as long as the exchange is not bound by any conditions. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.