Updated Oct. 21, 2013*
OMG you can illegally sell your kidney online - according to a Bloomberg TV segment Tuesday, Oct. 15, 2013. Bloomberg TV upped the ante with their video presentation "Cash on Hand: The Price of Body Parts" on the same date. Tastefully, BTV has left out some of the online links to illegally sell your body parts. But you may find those online links for the legal selling of "human essences" below.
One human "essence" of value is human hair. BTV lists the values of human hair from about "$100 to $1500". If recalled correctly the "$1500" is for top-notch hair of at least 18 inches in length. The Examiner cannot guarantee any of these values. The online market for buying/selling human hair given by BTV is www.buyandsellhair.com.
Human breast milk is also traded online. It has a value of about "$1.00 to $5.00 per ounce". Again, The Examiner cannot guarantee that. The online market for human breast milk is www.onlythebreast.com. It seems that they currently deal in 26 different categories of breast milk, donations and other services. It is suggested that you view/read their Terms before participating. Also, if you are embarrassed by images of human lactation well then you may want to avoid OTB. *Update of Oct. 21, 2013 : "Bacteria Found in Breast Milk Sold on Internet - ABC News http://abcn.ws/1fQhQyO".
The BTV video values the human ovum at around "$7K to $8.5K". The Examiner does not guarantee that and it may be best to consider donating any ova. There are at least two potential fertility services you may research online: First Fertility and Shady Grove Fertility Center. You may also connect to Shady Grove Facebook. Going by the Digital Journal article of Oct. 16, 2013 donors might be compensated.
According to the BTV video human organs may also be traded (online!) - but the buying and selling is generally illegal. "Black market" values for a human kidney are "about $15K" and a human liver (pieces of?) are "about $37K". Please do not engage in the practice of buying and selling your organs!
The hero of the attached video is a Mr. Beatrice (or his donor!) - who needed a kidney. Mr. Beatrice found his kidney donor (legally) on Facebook - please see the attached video: http://avideos.5min.com//81/5178081/517808003_2.mp4. He mentioned doing the research and finding the Facebook pages for the Living Kidney Donors Network and the National Kidney Foundation (link for the Michigan page). But - OMG - don't buy/sell your kidney online or in any market!