Not sure about the rest of the EU, but at least in Germany, plasma donations at private collection companies are a common way for students to earn beer money or end-of-month money, as you can donate plasma every couple days.

You also get paid for "normal" blood donations, even though the payment is technically only a "compensation" for your time and trouble. The donation services like German Red Cross usually still make a profit, which is why some people make a point to donate directly to hospitals if possible.