Reference for Bava Metzia 145:1

ברשות מוכר מותר ברשות לוקח אסור

if the vendor retains the title thereto, it is permitted; if the vendee, it is forbidden.<span class="x" onmousemove="('comment',' I.e., if the vendor bears the risk of carriage thither, it is not a loan, the vendee really selling it there on his behalf, and hence permitted. But if the vendee assumes responsibility, it immediately passes into his possession, and he is indebted for its value as a loan. Hence, since he repays more than it is worth where he receives it, it is usury. ');">¹</span> If he was transporting provisions from place to place, when his neighbour met him and proposed, 'Let me have them, and I will supply you [later] with provisions that I have there,' if he actually possesses provisions there, it is permitted;<span class="x" onmousemove="('comment',' For it is as though they were immediately transferred to the lender, and if they appreciate, it is the lender's which appreciates. ');">²</span>

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