I've been a blood donor for most of my adult life, and have donated about 30 liters. Where I'm at you get a token donation and a thanks for donating, but someone mentioned that in the US you get paid quite a lot depending on the quality and the blood type.
I have a fairly uncommon blood type (about 10% of the population) and a blood count of around 150.
So, how wealthy would I have been if I had donated my blood in the US instead?
Like the others I've only seen pay for blood plasma, not whole blood. Whole blood gets you a cookie, sometimes a sticker or a T-shirt, or once I got a $15 gift card but I'm pretty sure that was from the company sponsoring the charity blood drive and not the Red Cross who was collecting the blood.
And pay for plasma isn't a lot, like $30 a donation, 1-2 donations per week. You get more working a single shift at a fast food restaurant. Plasma also takes longer to donate than whole blood because you have to sit there while the plasma is separated out and the remainder pumped back into you.
They'd get less plasma. Putting the non-plasma portion back in what enables people to donate/sell plasma a couple times a week versus ~monthly or less if donating whole blood.
Also, we finally have the vampire bat population under control. We can't be feeding them that much blood, their strength will return and we'll be right back to the dark vampiric ages.