Is it permissible to buy an Amazon account charged with a sum of money ($1500) for less than its value (400 Saudi Riyals)?

It is not permissible to buy an account containing money with less or more money of the same currency, due to the presence of riba al-fadl (interest from surplus). However, it is permissible to buy it with a different currency, such as buying dollars with riyals, provided that possession is taken in the same sitting of the contract. This is based on the saying of the Prophet (peace be upon him): “Gold for gold, silver for silver, wheat for wheat, barley for barley, dates for dates, and salt for salt—like for like, equal for equal, hand to hand. If these types differ, then sell as you wish, provided it is hand to hand.” Monetary currencies are likened to gold and silver. Possession can be actual or constructive.