Is it permissible to give blood for money and then donate this money to the poor, knowing that giving blood is compensated in Germany?

There is no disagreement among scholars regarding the impurity of shed blood and the prohibition of benefiting from it, except in cases of necessity to save a patient's life. In such circumstances, it is permissible to benefit from it and donate it, provided that no harm befalls the donor. It is also permissible to request it from a Muslim or non-Muslim.

As for selling blood, it is unanimously forbidden, due to the Prophet's (peace be upon him) prohibition of the price of blood. However, it is permissible for a person in dire need to purchase it if it cannot be obtained without compensation. A donor is not allowed to sell blood, but there is no harm in accepting an unexpected incentive gift. Blood should only be donated to someone whose life is inviolable and when it is necessary.