That guy gave up rather...quickly. I dug a little more and found more information.

Sales

Searing Front Runner + 88 keys (7.4~)

Trade History: http://i.imgur.com/86inqUE.png + http://i.imgur.com/Smo2h2O.png

http://www.tf2outpost.com/trade/12388403

Sold for Phosphorous Baker's Boy + Keys (4.5~, I cannot find out how many, he offered Lime EA so...probably 5 keys..?) Looks like an obvious outlier.

Offers

http://www.tf2outpost.com/trade/12388403 (Same trade)

Self-Made Key + 2 (6~)

G.E. Batter's + Scorching Bombing Run +11 keys (6.4~, both prices old and outdated, though)

Bubbling Tower + Searing Noble + Peace Cockswain + Smoking Prancer's + Planets Mirror + 16 keys (7.9~, Tower and Mirror are outdated)

Mr. Bucket and Woifi both agreed this range is fine. Disagree and you'll have to fight them irl.

PS: They'll have no shirts on when you fight them.