An off beat way to make a few extra dollars

Years ago I had an interview with a company that made pharmaceuticals. They had blood plasma centers all over the USA. They would pay "donors" for their time to "donate" their blood plasma. At the time they were paying $50.00 for a 2 hour donation time. You could "donate" twice a week. I am thinking about calling the local blood plasma center and see how much they pay. I might be able to make an extra $200-300 a month which would pay off a few bills.