Is it permissible to sell a commodity in installments at a price higher than its market price, after purchasing it at a lower-than-market price, with a prior agreement to that effect?

If a screen is sold as a Murabaha (cost-plus sale) where the seller tells the buyer: "I bought it for 475 and I will profit such and such from it," this is forbidden deception. He must state the true price, which is 400, because Murabaha is among the trust-based sales in which the seller must declare the capital cost.

Trust-based sales are of three types: 1. Murabaha: A sale in which the price is set by adding a profit to the capital cost. 2. Tawliyah: A sale in which the capital cost itself is set as the price, without profit or loss. 3. Wadi'ah: A sale in which the price is set at a reduction from the capital cost.

If the seller increases the capital cost in a Murabaha sale, he must return the excess.