ENOfficial
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (may peace be'upon him) as saying: He who bought a goat having its udder tied up should go back with it, milk it, and, if he is satisfied with its milk, he should retair it, otherwise he should return it along with a sa' of dates.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ بْنِ قَعْنَبٍ، حَدَّثَنَا دَاوُدُ بْنُ قَيْسٍ، عَنْ مُوسَى بْنِ يَسَارٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنِ اشْتَرَى شَاةً مُصَرَّاةً فَلْيَنْقَلِبْ بِهَا فَلْيَحْلُبْهَا فَإِنْ رَضِيَ حِلاَبَهَا أَمْسَكَهَا وَإِلاَّ رَدَّهَا وَمَعَهَا صَاعٌ مِنْ تَمْرٍ " .
sunnah.com