Is it permissible for a person to sell a computer they bought for a known price back to the original seller for a lower price, even if it is with the consent of both parties?

If a person sells a commodity and receives its full price, then wishes to buy it back from the one who purchased it from him, there is no harm in that, whether he buys it back for less than he sold it, or for more, or for the same price, as the suspicion of usury is absent. However, if the first buyer has not paid the price of the commodity, it is not permissible for him to sell it back to the one from whom he bought it, in order to avoid the forbidden 'inah sale.