It is narrated from Sayyiduna Abu Sa'id (may Allah be pleased with him) that a group of the Companions of the Prophet (peace and blessings be upon him) set out on a journey. They stopped at one of the tribes of the Arabs and asked them for hospitality, but they refused to host them. Their chief was stung by some harmful creature. They tried everything for him, but it did not benefit him. Some of them said: If you go to these people who have stopped here (the Companions, may Allah be pleased with them), perhaps one of them has something that can benefit the chief. So some of them said: "O people of the caravan! Our chief has been stung by some harmful creature; we have tried (everything) for him. Is there anyone among you who can relieve our chief?" A man among the group said: "Yes! I can perform ruqyah, but we asked you for hospitality and you refused, so I will not perform ruqyah until you fix a payment for me." They agreed on a portion of sheep as compensation. That Companion came to him, recited Surah al-Fatihah over him and spat (lightly) on him, until he recovered as if he had been freed from a rope. They paid them in full what had been agreed. One of them said: "Divide it (the payment)," but the one who had performed the ruqyah said: "Do not do so until we go to the Prophet (peace and blessings be upon him) and ask him about it." In the morning they came to the Messenger of Allah (peace and blessings be upon him) and related the story. The Messenger of Allah (peace and blessings be upon him) said: "How did you know that it is a ruqyah?" And he said: "You did well; divide it, and keep a share for me along with you."
This indicates that one becomes entitled to a payment through a stipulation.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12122
It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) "ruled ten dirhams" for a runaway slave who is found in the Haram.
Ibn Abi Mulaykah and Amr bin Dinar (may Allah have mercy on them both) said that the Messenger of Allah (peace and blessings be upon him) "fixed ten dirhams" for a runaway slave who is found outside the Haram.
The first report is weak; what is preserved (mahfuz) is the second, and it is munqati' (its chain is broken).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12123
Sayyiduna Ali (may Allah be pleased with him) fixed one dinar (as the reward) for a runaway slave, whether he is found near or far.
And it is narrated from Amr bin Shu'ayb that Sa'id bin al-Musayyib (may Allah have mercy on him) used to say the same.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12124
Abu Amr al-Shaybani (may Allah have mercy on him) said: I found some runaway slaves. I came to Abdullah bin Mas'ud (may Allah be pleased with him) and told him, and he said: There is reward and gain. I said: The reward is there, but how is there gain? He said: Forty dirhams for each one.
This is the soundest of what has been narrated on this topic.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12125
Umar bin Sa'id (may Allah have mercy on him) narrates from a man of Khath'am called Hazn that he said: I brought a runaway slave from the army, but he escaped from me as well. They brought me before Shurayh, and Shurayh held me liable. This reached Sayyiduna Ali (may Allah be pleased with him), and he said: Shurayh has spoken wrongly and erred in his judgement. The black slave will be made to swear to the red slave: if he really escaped from him, then nothing is due from him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12126
It is reported from Sayyiduna Ali (may Allah be pleased with him) concerning a man who finds a runaway slave, and then the slave runs away from him as well, that Sayyiduna Ali (may Allah be pleased with him) did not hold him liable, whereas Shurayh (may Allah have mercy on him) held him liable.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12127