Sale #1

http://www.tf2outpost.com/trade/19960630

Sold for 2 buds pure

Backpack of seller

http://backpack.tf/profiles/76561198041401847?time=1402297200 before

http://backpack.tf/profiles/76561198041401847?time=1402383600 After

Backpack of buyer

http://backpack.tf/profiles/76561198055457557?time=1402038000 Before

http://backpack.tf/profiles/76561198055457557?time=1402423811 After

Total: 2 buds

Sale #2

http://www.tf2outpost.com/trade/21459534

Sold for 2 buds + 10 keys pure.

Can't really see it from the backpack but it is confirmed by polar in here http://backpack.tf/vote/id/53e4df034f96f4b7588b4568

Total: ~2.5 buds

Invalid sales

Sale #3

http://www.tf2outpost.com/trade/21211179

Sold for Flipped Trilby Kill-a-watt(Outdated)

Sale #4

http://www.tf2outpost.com/trade/21218244

Sold for Orbiting Fire L'homme Burglerre(Not priced)

Sale #5(Clear outlier)

http://www.tf2outpost.com/trade/21232006 b/o 2.5 buds

Traded this + Dead Presidents Hottie's Hoodie(2.15 buds) for Wraith Wrap Miami Nights(3 buds)

Sale #6

http://www.tf2outpost.com/trade/21277372

Can't identify sale

Sale #7

http://www.tf2outpost.com/trade/21280655

Traded this + Cloud Crasher Orbiting Planets(Outdated) for duped Scorching Flames Big Elfin Deal(Outdated)

Why don't you mini suggest the outdated hats? I don't think that it is necessary as the sales with overpay applied most likely will fall within the range. And also, the b/o of 2.5 buds of Sale #5 sort of sets the high end.