To buy an iPhone 4S. To pay for an abortion for a girlfriend. To redeem a truck.

Just some of the reasons why many Chinese people are lining up to sell their kidneys to underground organ traffickers.

With more than a million patients in urgent need of kidney transplants each year and many healthy and willing donors desperate for cash, the illegal trade is booming, Nanfang Daily reported. Only 4,000 legal kidney transplants took place last year.

Some traffickers wander around hospitals every day, seeking patients who could become their next buyers. And there is a well developed network seeking out volunteers to become "kidney donors," the newspaper found.

After an operation at an underground hospital, He Qing, a 32-year-old Anhui Province native, received 20,000 yuan (US$3,167) in cash - as well as a 12-centimeter scar "twisting on my stomach like a crawling centipede," he said. He could finally pay off his debts, go to the barber, and buy himself a cell phone. But lacking one of his kidneys, his health has been deteriorating. "I'm starting to regret selling the kidney," he told the newspaper. "I'm getting thinner and paler each day. If I'd worked hard in the past few months, I could have earned the money with my hands, not my kidney." He said he used to have a good job and a happy family life. But when his wife left him with their daughter, he quit his job and turned to drink. Eventually he owned more than 15,000 yuan on two credit cards.