the only relevant material is the 99+% stuff and priced directly from the producer (only a couple of mines produce any of significant quanity).

here's an example: http://graphite.com.co/online-store/#!/~/product/category=5291633&id=22604951

http://graphite.com.co/online-store/#!/~/product/category=5291576&id=22607112

http://graphite.com.co/online-store/#!/~/product/category=5487193&id=27768178

i'm sure if you want larger quantities (if you can get it as they sell out every year), the price will be a bit lower.

http://graphite.com.co/who-we-are/