Sayyiduna Ali (may Allah be pleased with him) found a dinar and bought flour with it. The flour seller recognised him and returned the dinar to him. Sayyiduna Ali (may Allah be pleased with him) took it and bought two qirats' worth of meat.
There is inconsistency in the text of this hadith, and there is weakness in its chains.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12095