There are only 2 existing at the moment and only one of them is at the market.

It was sold 8 times:

From Bandicoot to SergeyX64TM for an orbiting fire Respectless robo-glove(1,4 buds): http://www.tf2outpost.com/trade/15378592

From SergeyX64TM to Sherlock Homie [Big Pink] (price not known)

From Sherlock Homie [Big Pink] to иℰχт∂σσяsρσσтℐs for 2 buds:

http://www.tf2outpost.com/trade/15520609

From иℰχт∂σσяsρσσтℐs to SoyMilk for 1 Max Severed Hat(2,2-2,3 buds):

http://www.tf2outpost.com/trade/15567203

From SoyMilk to Nickps(price not known but over 1,8 buds):

http://www.tf2outpost.com/trade/15741447

From Nickps to Steve French for a circling tf2 logo desert Marauder(1,8 buds):

http://www.tf2outpost.com/trade/16600801

From Steve french to Derpyx2 for 2 buds:

http://www.tf2outpost.com/trade/16687655

From Derpyx2 to NiceGuy for Terror Watt Berliner´s Bucket Helm(price not known)

Summary: (1,4+2+2,3+1,8+2)/5= 1,9 buds

range: 1,7-2 buds