The Prophet ﷺ forbade meeting traders on their way to the market to buy their goods. If someone does meet them and purchases their goods, the owner of the goods retains the right to cancel the sale once he reaches the market.
حدثنا سلمة بن شبيب حدثنا عبد الله بن جعفر الرقي حدثنا عبيد الله بن عمرو عن أيوب عن محمد بن سيرين
أن النبي ﷺ نهى أن يتلقى الجلب فإن تلقاه إنسان فابتاعه فصاحب السلعة فيها بالخيار إذا ورد السوق
Its isnad is sahih. Abu Dawud narrated it in the Book of Business Transactions, chapter on meeting traders before they reach the market, hadith no. 3437, from the hadith of Ubaydullah bin Amr, and Muslim narrated it, hadith no. 1519, from the hadith of Muhammad bin Sirin, with the same wording.