Sayyiduna Imran bin Husayn (may Allah be pleased with him) says that the Prophet (peace and blessings be upon him) ransomed one man in exchange for two men.
(b) The woman whom Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) gave to the Messenger of Allah (peace and blessings be upon him), the Messenger of Allah (peace and blessings be upon him) obtained several captives in exchange for her.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18826