Donating blood for transfusion comes under the category of performing beneficial deeds (see Leviticus 19:18 and Zecharia 7:9). The merit of this virtue is also mentioned in Proverbs 21:21. Subsequently, the highest in percentage of blood donors in Israel is in the Orthodox Jewish sector.
There is no problem with receiving money for the blood as long as the laws of your locale do not prohibit it. It is a mitzvah to donate, whether for remuneration or not. Therefore donating blood, plasma or platelets is a mitzvah that one can receive benefit from in this world.
