I used to donate when I was going to college. They used to pay something like 50 bucks per session and during this time, it was free beer money!
I don't really remember any pain from it. One time I had a nurse (must have been one of her first tries) miss the vein and it rolled over and I looked like a junkie for a week. Never go though after you have been out drinking... Takes twice as long due to the dehydration.
