My first suggestion here :3

http://www.tf2outpost.com/trade/10023581

-B/O 19

-Got offerd Treasure hat+sweets but didnt take it

-after 2 days

http://www.tf2outpost.com/trade/9681172

-B/O 20 keys

-Was offerd 17 pure and rejected it

-after 2 weeks

http://www.tf2outpost.com/trade/6384980

-B/O 30 keys

-C/O 15 keys

-After 4 months

http://www.tf2outpost.com/trade/9952360

-B/O 18 keys

-No C/O

-after 6 days

http://www.tf2outpost.com/trade/10074289

-B/O 21 keys -

No C/O

-after 1 day

http://www.tf2outpost.com/trade/10093622

-B/O 20 keys

-someone added him but dont believe he is willing to pay the B/O as there are few other of these having a lower B/O

http://www.tf2outpost.com/trade/9470560

-B/O bud

-No C/O

-after 3 weeks

http://www.tf2outpost.com/trade/10040248

-No B/O

-No C/O

-After 3 days

http://www.tf2outpost.com/trade/10045539

-B/O 15 keys

-C/O guy collecting the 15 keys

-after 1 day

So basically what we see, there is 0 interest in this hat, weeks and not a single offer.

On the other side the one selling for 15 keys had a buyer in 24 hours,another one rejected 15 keys and someone else was offerd 17 keys.

But it cant be ignored that half of them, have no C/O at all.

Not sure if the suggested price is good or not but those are the only values i found.

Cheers