Sale with advance payment

Q: I have a question and I thankfully wish Your Eminence would (Part No. 11; Page No. 128) provide me with an answer.1- I want to represent a company by being its agent in the Kingdom and by presenting a sample of its products. If the customer wishes to buy any of the company's products, I will send it a message to get the price list and the time that the order will take to be delivered. I will take 30 % of the order value from the customer and the rest when the order is actually delivered. Is this a Shar`y (Islamically lawful) transaction?2- Sometimes a government authority or a specific company submits a tender to secure some stationary or electric tools or any other needs. I present an offer with a price for such demands, knowing that I only possess some of them. I go to merchants to give me prices for such commodities because they are their importers and I add a slight percentage over the prices that I get. If they ask me to bring the commodities, I go and buy them from the market. Is that permissible in Shari`ah (Islamic law) or is it considered as selling what I do not possess? Please advise, may Allah reward you.

A: What you mentioned in both questions is considered a Salam sale (sale with advance payment). So, if the commodities are specified via description and their total value is handed over in the same session, and the date of its delivery is known, the contract will be valid. However, (Part No. 11; Page No. 129) if part of the price, not the total price, is handed over in the same session of concluding the contract, then the contract will be invalid because it is selling a debt for a debt.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.