Is it permissible to purchase a computer from a supermarket in installments without interest, provided that there is a purchase fee paid at the time, knowing that this method is followed in Spain?

It is permissible to purchase a computer or other items by installments at a price higher than its cash price, in exchange for the deferment. As for purchase fees, if they are part of the accelerated price, there is no harm in them. If they are not, then it is impermissible to pay them, because they constitute consuming people's wealth unjustly, and "do not consume your property among yourselves unjustly," and "do not cooperate in sin and aggression." An exception to this is a case of necessity, if a person is compelled to make the purchase and cannot do so except by paying these fees, based on the Almighty's saying: "And He has detailed for you what He has forbidden you, unless you are compelled to it." Necessity is that which leads to perishing or extreme hardship.