Is the price considered specified in a Salam transaction if the two parties agree to determine it based on the market price at the time of delivery three months later, and is the transaction valid if they agree on a 10% discount from the price determined at the time of delivery?

The described transaction is not valid because it is a condition that the price be determined and fully paid at the time of the contract. Determining it upon delivery of the commodity is impermissible and falls under the category of selling debt for debt, in addition to the ambiguity in the price. The second part of the question is not permissible because the price is unknown, and what was handed over at the time of the contract is not a real price, but rather a pledge or a loan.