Proof below. Overpay calculated

Solds

http://www.tf2outpost.com/trade/13677912 - White Bills + 12 keys + TC = 20 keys

http://www.tf2outpost.com/trade/11558739 - A bunch of stuff + Tuxxy (mentioned in comments) for 30 keys. Makes the Mirror = 26 keys (outlier)

http://www.tf2outpost.com/trade/11558739 - Mirror + Orb Fire Tricorne for a Bubbling Towering, Mirror = 18 keys

Side note: Took mid-price of Towering since it was offered on

B/O's to disprove 26 key sale

http://www.tf2outpost.com/trade/14364618 - 25 keys

http://www.tf2outpost.com/trade/14371730 - 21 keys

http://www.tf2outpost.com/trade/14331909 - 21 keys

http://www.tf2outpost.com/trade/14003985 - 21 keys

http://www.tf2outpost.com/trade/14263853 - 20 keys (Quicksell?)

Conclusion

2 sales, with the 26 key sale seemingly too high. Vote accordingly.

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