In America, blood is big business. It makes up 2.69 percent of total exports and the U.S. also supplies 94 percent of the paid plasma used globally. Most countries have banned compensated blood donations, but the U.S. allows a person to "donate" plasma twice a week, or 104 times a year, for an average of $35 to $65 per visit.

Eleazar Sanchez is a Mexican immigrant who makes extra money by "donating" plasma eight times a month, for which he receives $500 that he uses to pay bills and rent. Eleazar said the plasma center is flooded with low-income people and that he's seen more centers opening recently.