As an extension of the organ donor program, the Lifeline act was passed in 2010 allowing a potential source of spare parts to carry a donor card in his wallet. This card must be registered with the federal government. Upon death, a carded donor’s body can be turned over to a registered body bank, which will pay a bounty based on the condition of the body. Anyone bringing in a body with matching donor card and a death certificate stating that the death was caused by accident or natural causes can collect the fee.
That is how it works legally. There are also plenty of black market body banks that will offer cash for body parts, no questions asked. The bounty is a lot less, but no donor card or death certificate is required.
On the other side of the coin, if you lose a limb or other important body part, and don’t want to get an artificial replacement, you can go to a body bank and get the real thing. The trick is, not only do they have to have the right part, but it needs to be a close enough genetic match that your body won’t reject it. But if you are trying to avoid the humanity loss, the body bank can’t be beat.