Whoever buys a sheep which has not been milked for a long time, has the option of returning it along with one Sa of dates; and the Prophet ﷺ forbade going to meet the seller on the way (as he has no knowledge of the market price and he may sell his goods at a low price).  

مَنِ اشْتَرَى شَاةً مُحَفَّلَةً فَرَدَّهَا فَلْيَرُدَّ مَعَهَا صَاعًا وَنَهَى النَّبِيُّ ﷺ أَنْ تُلَقَّى الْبُيُوعُ