Sunan Ibn Majah, Book 12, Hadith 2324 (In-Book) ⓘ
It was narrated from Ibn 'Umar that the Prophet said: "O Allah, bless my nation in their early mornings.". It was narrated from Abu Hurairah that the Prophet said: "Whoever buys a Musarrah, he has the choice (of annulling the deal) for three days. If he returns it, then he must also give a Sa' of dates, not Samra'." Meaning wheat.
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَعَلِيُّ بْنُ مُحَمَّدٍ، قَالاَ حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامِ بْنِ حَسَّانَ، عَنْ مُحَمَّدِ بْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ ـ صلى الله عليه وسلم ـ قَالَ " مَنِ ابْتَاعَ مُصَرَّاةً فَهُوَ بِالْخِيَارِ ثَلاَثَةَ أَيَّامٍ فَإِنْ رَدَّهَا رَدَّ مَعَهَا صَاعًا مِنْ تَمْرٍ لاَ سَمْرَاءَ " . يَعْنِي الْحِنْطَةَ .
also referenced under: Hadith 2238 (Reference) & Volume 3, Book 12, Hadith 2238 (DarusSalam)