Sahih Muslim | Book 10 | Hadith Number 3636
Narrated by Abu Huraira (Allah be pleased with him)
Abu Huraira (Allah be pleased with him) reported Allah's Apostle (may peace be upon him) as saying: lie who buys a goat having its udder tied up has the option to return it within three days. If he returns it he should pay a sa' of dates. Wheat is not essential.