Is It Prohibited to Sell Blood?
Question

The blood bank gives a gift to those who donate blood, which is a prayer mat, medallion or headcover, etc. Sometimes they give three hundred riyals. I hope you can explain the Islamic view on these gifts?
Praise be to Allah.This is regarded as selling blood, and selling blood is prohibited according to scholarly consensus.
It says in Fatawa Al-Lajnah Ad-Da’imah lil-Buhuth Al-`Ilmiyyah wal-Ifta’ (13/71):
It is not permissible to sell blood, because of the report in Al-Bukhari from Abu Juhayfah (may Allah be pleased with him) who said that he bought a cupper (as a slave) and ordered that his equipment be broken. He was asked about that and he said: The Messenger of Allah (peace and blessings of Allah be upon him) forbade the price of blood.
Al-Hafidh Ibn Hajar (may Allah have mercy on him) said in Al-Fat-h: What is meant is that it is prohibited to sell blood just as it is prohibited to sell dead meat and pork, and it is prohibited according to scholarly consensus, i.e., to sell blood and take its price. (End quote)
It says in Al-Mawsu`ah Al-Fiqhiyyah (9/148):
It is prohibited, and the contract is invalid, to sell “blood poured forth” because Allah says (interpretation of the meaning):  “… or blood poured forth (by slaughtering or the like),” [Al-An`am 6:145].
Ibn Al-Mundhir and Ash-Shawkani (may Allah have mercy on them) stated that there was consensus among the scholars on the prohibition on selling blood. (End quote)
For more details, please see the following answers:
Rewards for donating blood
Donating blood to Blood Bank
Can Muslims Donate Blood to Non-Muslims?
The administration of the blood bank is forcing clients to donate blood
Does Blood Donation Break Wudu?
Are Blood Transfusions Haram in Islam?
And Allah knows best.