Proof below. Overpay calculated

Sales

http://www.tf2outpost.com/trade/13885122 - Pink BMOC, other guy added a key = 14 keys

http://www.tf2outpost.com/trade/12870691 = 14 keys

http://www.tf2outpost.com/trade/13862605 - 14 keys + White Bills = 21 keys (outlier)

B/O's To Prove 21 keys is an outlier

http://www.tf2outpost.com/trade/14314639 - 19 keys (5 days)

http://www.tf2outpost.com/trade/13563481 - 18 keys (1 month)

Notable Offers

http://www.tf2outpost.com/trade/13563481 :

- Bubbling One Man Army = 15 keys

- Smoking Bucket + Unknown Sweets = 16 keys (?)

- Smoking Officer's Ushanka = 16 keys

Conclusion

2 sales at 14, but offers higher.

Help / Constructive Criticism / Additional Proof / Counter-Proof is ALWAYS welcome! >;3