If you dont mind needles it isnt a bad thing... remember you are not donating your blood, or selling blood... One can only donate blood every 8 weeks... this is for the plasma, the machine you are hooked up to separates the plasma from the red blood cells and returns them to you.
Havent done it since my ex wife was still in school (I wanted to have spending money, but paying all the rest of the bills didnt afford me that luxury, this was simple enough)... I dont even know how much they pay now, but you make money from it thats tax free, and the plasma goes to help others... especially the plasma center, like I mentioned before, they make a ton off of the stuff. I wouldnt have known I was low on my blood protein levels had I not donated years ago.
BioLife is currently paying $50 for the first four donations (as you know, you can only donate twice per week). After those $200, you get $20 for the first donation of the week and $40 for the second donation of the week ($60 per week, total)... and a $20 bonus for the 7th donation (end of the month)...
So, you get, every month:
First week: $60
Second week: $60
Third week: $60
Fourth week: $80
Total: $260 per month, tax free.
Good extra cash.