Sayyiduna Suwayd bin Qays (may Allah be pleased with him) reported: Makhrafah and I (may Allah be pleased with them both) brought cloth from Hajar or Bahrain. When we were at Mina, the Messenger of Allah (peace and blessings be upon him) bought a pair of trousers from me. He said: There was a weigher there who weighed for a wage. The Messenger of Allah (peace and blessings be upon him) gave him the price and said: "Weigh, and give good weight."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11169
Malik bin Amirah (may Allah be pleased with him) said: Before the Hijrah, the Messenger of Allah (peace and blessings be upon him) bought from me cloth for a pair of trousers for three dirhams. He (peace and blessings be upon him) gave me three dirhams and gave me extra as well.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11171
Abu Safwan bin Amirah (may Allah be pleased with him) said: I came to the Messenger of Allah (peace and blessings be upon him) in Makkah before the Hijrah and sold him cloth for a pair of trousers. He (peace and blessings be upon him) paid me its full price and gave me extra as well.
Abu Dawud said: Qays narrated it as Sufyan said, and the correct view is that of Sufyan. Shu'bah said: Sufyan had a better memory than me.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 11172