Not much proof since its fairly new, but regardless

http://www.tf2outpost.com/trade/11651439 (Offered orb fire brainac, 2.5-3.3 on bp.tf, also offered a power surge softcap and sweets, that softcap apparently had a co of 4 pure

http://www.tf2outpost.com/search/120483074 <-- 2 for sale

http://www.tf2outpost.com/trade/11317557 Offered a backpack that had a few nice unusuals ( Here is his OP profile http://www.tf2outpost.com/user/251606 )

Sorry if its bad, im new to suggestions, but i think this is a fairly good starting price