Musannaf Ibn Abi Shaybah

Hazrat Hammad says regarding a person that if someone gives goods to another as mudarabah and sets the price of the goods at one thousand dirhams, then he sells it for nine hundred dirhams, he said the principal amount will be nine hundred dirhams.

Hazrat Hasan (may Allah be pleased with him) regarding this issue says that if a person gives goods to another as mudarabah and both of them assess its value, he said that the value at which the goods were assessed will be considered the principal (ras al-mal), and its own price has no significance.

Hazrat Tawus (may Allah have mercy on him) says that there is no harm if a person estimates the price of another item and then gives it on that price as a mudarabah.