Here are details regarding how the ghost towns are funded and why China keeps building them so far from present city centers.

"It is hoped that these new towns will, in addition to alleviate urban congestion, spark further in-fill development in the expanse of farmland that sets the new town apart from the city center – a kind of pre-planned suburban sprawl. Funding for these new towns comes from the difference paid to compensate farmers to relocate (a calculation based on potential agricultural yields) and the substantially higher revenue generated from leasing the same land to developers." http://blogs.worldbank.org/transport/rise-of-the-chinese-gho...

In the comments the author also mentions that many of these buildings are offered at below cost to government employees.