Well this is overpriced...

Sale 1:

http://backpack.tf/profiles/76561198119628715#!/compare/1496707200/1496793600

M.Nights Robo glove(12.5) + Bubbling Sola(9) ~ 21.5

Sale 2:

http://backpack.tf/profiles/76561198167670940#!/compare/1496793600/1496966400

(13 keys)

Sale 3:

http://backpack.tf/profiles/76561198176814243#!/compare/1497052800/1497312000

(14 keys)

Sale 4:

http://backpack.tf/profiles/76561198089433218#!/compare/1497312000/1497398400

(15 keys)

Sale 5:

Bought for 15keys 14 ref from bot

http://backpack.tf/profiles/76561198133814251#!/compare/1494633600/1494720000

Then sold back to bot for 15k

http://backpack.tf/profiles/76561198133814251#!/compare/1494720000/1495238400

This has happened multiple times:

http://backpack.tf/item/1162581742

Unsolds:

http://imgur.com/XRj3FFT (Young sellers all less than 16 keys)

http://www.tf2outpost.com/trade/29226672 (4 days at 14 keys)

http://www.tf2outpost.com/trade/29229435 (2 days at 16 keys)

{Minis}

ROBO GLOVE

http://backpack.tf/profiles/76561198049834485#!/compare/1497312000/1497398400

Sold with 2 keys for a Bubbling tyrants helm(14.5 keys)

14.5 - 2 = 12.5

SOLA TOPI

2 month old price

http://backpack.tf/suggestion/59076f6be3387756db7fad5a

Seller at 9 keys

http://www.tf2outpost.com/trade/29226130

Going with (9)

Sales

*13* , 14 , 15 , *21.5*

** Buyer for 13 discarding

** Outlier at 21.5

Unsold at 14 and ~ 15

Going with 14 - 15

Any help appreciated, first unusual suggestion.

+ EDIT 1: SOLA price was edited due to seller at 9 keys, overall suggestion not affected