What is the preponderant opinion of Sheikh Ibn Uthaymeen regarding the ruling on the remainder of the commodity's price staying as an "amanah" (trust) with the seller if he does not have change at the moment of sale? And is the reasoning that it is an "amanah" strong, or is the reasoning of "subordinacy" more preponderant? And does the reasoning of "amanah" apply to pure exchange (sarf)?

There is no harm in the buyer leaving the remaining amount with the seller if the seller does not have change, and this is considered a trust, whether they agree to retrieve it after a short or long time. The Permanent Committee for Issuing Fatwas stated that the buyer leaving some of his money with the seller is not usury; rather, it is a matter of entrusting the seller with the rest of the price, and it is not a currency exchange transaction. The report favored the view that considering the remaining amount as a trust is a strong and appropriate interpretation for the excess remaining with the seller.