From Sahih Bukhari (Hadith 2149):
Narrated `Abdullah bin Mas`ud: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)
Reference: Bukhari 2149