RMB7771.40 (equivalent to about US$1267 before shipping costs) from http://item.jd.com/
If you are located in Singapore, you can buy it via www.sgshop.com.sg
You can purchase it via taobao agent www.taobaoring.com
However, if you prefer to read them as PDFs on your fancy schmancy iPad mini, you can also download them at this link or better yet, at this treasure trove of an archive.
And, definitely check out this archive full of guqin scores for dapu. (thanks to Jim for sharing the info!)