סימן סה סעיף יח
מִי שֶׁיֵּשׁ לוֹ סְחוֹרָה שֶׁנִּמְכֶּרֶת כָּאן בְּזוֹל וּבְמָקוֹם אַחֵר בְּיֹקֶר, וְאָמַר לוֹ חֲבֵרוֹ: תְּנָה לִי סְחוֹרָה זֹאת וְאוֹלִיכֶנָהּ לִמְקוֹם הַיֹּקֶר וְאֶמְכְּרֶנָּה שָׁם וְאֶעֱשֶׂה צְרָכַי בַּמָּעוֹת עַד זְמַן פְּלוֹנִי, וְאֶפְרְעֶנָּה לְךָ כְּפִי מַה שֶּׁהָיָה שָׁוָה שָׁם לְאַחַר נִכְיוֹן הַהוֹצָאוֹת שֶׁעָלוּ עַל הַסְּחוֹרָה, אִם הָאַחְרָיוּת בַּהֲלִיכָה הָיְתָה עַל הַלּוֹקֵחַ, אָסוּר. וְאִם הָאַחְרָיוּת עַל הַמּוֹכֵר, מֻתָּר. וְהוּא שֶׁיִּתֵּן לְהַלּוֹקֵחַ אֵיזֶה דָּבָר בִּשְׁבִיל טָרְחוֹ.
One who has merchandise that sells here at a low price and elsewhere for a higher price, and his friend says to him: "Give me this merchandise and I will transport it to the place where the higher price [can be obtained]. I will sell it there and use the money for my own needs until such and such a time, and I will repay you according to what it sells for there, minus the expenses incurred [in transporting and selling] the merchandise".34In effect, his friend, the buyer, has borrowed money from him and the lender (the seller) gains in two ways: 1) the return of his money for the goods at the higher price, 2) the work and effort which his friend put into selling the product. If the risk in transit [for the merchandise] was taken by the buyer, it is prohibited.35From the moment his friend accepts responsibility, it is considered in his friend’s possession and on loan to him. Thus, he has borrowed goods worth the lower price with the stipulation that he will repay at the higher price. Ribis is incurred. But, if the responsibility [remains] with the seller, it is permitted,36Since the seller has retained responsibility for anything that might happen to the merchandise, he retains possession and it is his that is sold at the higher price and he is entitled to the profit. provided that he compensates the buyer with something for his bother.37Though the seller is entitled to the higher price (as per note 36), nevertheless, his friend did borrow the money and the seller, besides being repaid, benefits from the toil and bother incurred by his friend in selling the product. Thus, by compensating the friend for the toil, he cancels that benefit and the result is not ribis.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)