Narrated Hakim ibn Hizam:

The Messenger of Allah ﷺ sent with him a dinar to buy a sacrificial animal for him. He bought a sheep for a dinar, sold it for two and then returned and bought a sacrificial animal for a dinar for him and brought the (extra) dinar to the Prophet ﷺ. The Prophet ﷺ gave it as alms (sadaqah) and invoked blessing on him in his trading.

حَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ الْعَبْدِيُّ، أَخْبَرَنَا سُفْيَانُ، حَدَّثَنِي أَبُو حُصَيْنٍ، عَنْ شَيْخٍ، مِنْ أَهْلِ الْمَدِينَةِ عَنْ حَكِيمِ بْنِ حِزَامٍ، أَنَّ رَسُولَ اللَّهِ ﷺ بَعَثَ مَعَهُ بِدِينَارٍ يَشْتَرِي لَهُ أُضْحِيَةً فَاشْتَرَاهَا بِدِينَارٍ وَبَاعَهَا بِدِينَارَيْنِ فَرَجَعَ فَاشْتَرَى لَهُ أُضْحِيَةً بِدِينَارٍ وَجَاءَ بِدِينَارٍ إِلَى النَّبِيِّ ﷺ فَتَصَدَّقَ بِهِ النَّبِيُّ ﷺ وَدَعَا لَهُ أَنْ يُبَارَكَ لَهُ فِي تِجَارَتِهِ .