(Yoosuf) 12 : 62
وَقَالَ لِفِتْيَانِهِ اجْعَلُوا بِضَاعَتَهُمْ فِي رِحَالِهِمْ لَعَلَّهُمْ يَعْرِفُونَهَا إِذَا انْقَلَبُوا إِلَىٰ أَهْلِهِمْ لَعَلَّهُمْ يَرْجِعُونَ
And he said to his servants: "Put their merchandise into their saddlebags so that they might recognize it when they have reached back to their family and so that they will come again".
As the barter system existed for trading during that time, Yoosuf told his servants to return whatever his brothers had brought for buying the grains.