Quite a few other sellers your missing (although yours seems the most recent)

http://www.tf2outpost.com/trade/24593913 - 5 (4 days)

http://www.tf2outpost.com/trade/24583353 - 5.66 (5 days)

http://www.tf2outpost.com/trade/24589091 - 5.66 (4 days)

http://www.tf2outpost.com/trade/24561023 - 6 (5 days)

http://www.tf2outpost.com/trade/24632529 - 6.33 (2 days)

http://www.tf2outpost.com/trade/24646855 - 6.66 (1 day old)

http://www.tf2outpost.com/trade/24625873 - 8 (2 days)

http://www.tf2outpost.com/trade/24553749 - 8 (6 days)

http://www.tf2outpost.com/trade/24518061 - 6 (This one may not be very valid, I'm not sure when trades are considered old except for after a week)

Your seller is extremely young, and there are a handful of other sellers that either sell from 5 ref to current price.