What is the ruling on deferred-payment sales, and is increasing or decreasing the price of a commodity considered usury?

It is permissible to sell on credit at a price higher than the cash price. It is also permissible to reduce the price of a commodity, whether sold on credit or for cash, because this falls under leniency and facilitation. The Prophet, peace and blessings be upon him, said: "May Allah have mercy upon a man who is lenient when he sells, when he buys, and when he demands his rights."