Al-Kāfi

Hadith 1813
temporary-marriage
5- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ مُحَمَّدِ بْنِ عِيسَى عَنْ يُونُسَ عَنْ بَعْضِ أَصْحَابِنَا عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ أَدْنَى مَا تَحِلُّ بِهِ الْمُتْعَةُ كَفٌّ مِنْ طَعَامٍ وَرَوَى بَعْضُهُمْ مِسْوَاكٌ.
5. Ali ibn Ibrahim has narrated from Muhammad ibn ‘Isa from Yunus from certain persons of our people who have said the following: “Abu ‘Abd Allah (a.s.), has said, ‘The minimum amount of mahr (dower) in al-Mut‘ah (advantageous marriage) can be even a handful of food.’ Certain ones of them have narrated that even a Miswak (toothbrush) is acceptable.”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī