Plagiarism
'A former Oxford university student has said graduates can earns up to £30,000 a year by writing essays and selling them to school and university students. The writer, who is in his 20s and wanted to remain anonymous, said he was commissioned by a firm that sells essays by Oxford graduates on the web.
Students are charged between £70 for GCSE essays and £20,000 for PHD work. [...] The graduate said he gets paid about £500 for an undergraduate essay. [...]
"I don't have a problem with it - it's not selling drugs, just using your brain. I went to private school so I see it as recuperating some of those costs. I've spent a lot of money on my education. It's only fair enough if I can make a little bit directly off it."'
(BBC)
If true, this is stunning.
Though here's a reason to be suspiscious of the accuracy of this report: £20,000 seems like an oddly low figure for PhD level work. If such people earn up to £30,000 in a year, then it presumably takes them around nine months to write a passable PhD. That seems unlikely.
The quotes at the end are also obviously wrong. Having been to private school and university costs money precisely because it already priveleges you in life. You don't deserve further compensation for such advantages.

Plagarism
I'm not surprised.
Also if you are good at writing thesis you can write them much faster than other people.
the price seems around what I would expect in my country if you translate pounds into dollars - its about the same price as fake Permanant Residency.
I imagine that
1) Students tend to have limited current resources
2) the supply of good thesis writers is reasonably good so one could easily be undercut
3) good thesis writers can write them much faster than the average student, particularly if they have already done the reading for the field.
Interesting thing to me is that a supervisor could be fooled by it, sure on an essay but on a PHD? maybe the institutes have something to answer for.
Anyway this seems popular amongst people from Asia, having said that I don't really know all that many non-asians closely enough for them to tell me so maybe they are doing it too.