Suppose 20 qafiz of wheat is bought for an agreed immediate monetary price.
1. The seller supplies and measures the promised grain; the stated measurer's fee falls on the seller.
2. If the agreed money is weighed, the buyer furnishes its proper weight and pays the price weigher.
3. For the normal cash sale, the buyer pays and then the seller properly delivers the grain.
Keep quantity of goods, quantity of payment and order of delivery distinct.