Literally less than a page on outpost. Shame too, scarves are hella.

Sellers below 6 keys:

http://www.tf2outpost.com/trade/19443230 Selling for 5 keys 5 ref, ~5.66 keys.

http://www.tf2outpost.com/trade/19192314 Selling for 5 keys 6.66 ref, ~5.88 keys.

http://www.tf2outpost.com/trade/19433950 Selling with parts for 6 keys, I can't really gauge the price but that would put the price somewhere below 6 keys.

http://www.tf2outpost.com/trade/19410347 Selling for just 5 keys, underbumped, let's call it an outlier.

http://backpack.tf/classifieds/search/id/534427d04dd7b838288b4a8e also has some sellers below 6 at the moment.

However, they're just the first and second links.

But wait! The second link, BOSNIA..., has reduced his price to 5 keys 4.88 ref, or ~5.66 keys! Radical! Also, the third classified link happens to be the guy selling with a part for 6 keys, so that's a thing.

In all, we have 2 sellers at 5.66 and one seller somewhere below 6. That may not seem like much, but in a world with 1 OP page, that's basically the market. I can't disprove 6 though, and a lot of the market is still selling at that price, so I'm not excluding it from the range.