Amr bin Harish said: I said to Abdullah bin Amr bin al-As (may Allah be pleased with them both): We live in a land where there is no gold or silver; may we buy one cow for two, one camel for two camels, and one goat for two goats? Abdullah bin Amr bin al-As (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) ordered me to equip an army, and the camels ran out. I said: O Messenger of Allah (peace and blessings be upon him)! The camels have run out. He (peace and blessings be upon him) said: "Take the sadaqah camels." He said: So I would take one camel for two, (payable) from the sadaqah camels.
The narrators differed over Muhammad bin Ishaq in its chain; Hammad bin Salamah's version is the best of them in wording, and it has an authentic supporting report (shahid).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10528
Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) ordered him to equip an army. Abdullah bin Amr (may Allah be pleased with them both) said: We had no mounts. He (peace and blessings be upon him) said: "Buy mounts (to be paid for) when the sadaqah camels arrive." So Abdullah bin Amr (may Allah be pleased with them both) bought one camel for two camels, (payable) when the sadaqah camels arrived, by the order of the Messenger of Allah (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10529
وَأَخْبَرَنَا أَبُو زَكَرِيَّا، ثنا أَبُو الْعَبَّاسِ، أنا الرَّبِيعُ، أنا الشَّافِعِيُّ، أنا مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ " أَنَّهُ اشْتَرَى رَاحِلَةً بِأَرْبَعَةِ أَبْعِرَةٍ مَضْمُونَةٍ عَلَيْهِ يُوفِيهَا صَاحِبَهَا بِالرَّبَذَةِ ".
Nafi' narrates from Ibn Umar (may Allah be pleased with them both) that he bought a riding camel for four camels, which he guaranteed to deliver to its owner at al-Rabadhah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10531