Ata narrated from Sayyiduna Jabir bin Abdullah (may Allah be pleased with them both) that one of the Companions of the Prophet (peace and blessings be upon him) freed his slave as a mudabbar, and he had no other wealth, so the Prophet (peace and blessings be upon him) sold him for 800 dirhams and gave the price back to the owner.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المدبر / 21545