Counter-suggestion: http://backpack.tf/vote/id/52cf33194dd7b84a598b4568 -

Original values of unusuals used and overpay applied when necessary. Buds and keys what they were time of sale

Proof #1

http://www.tf2outpost.com/trade/16313341

Added a PE Cowl (~5.4) for a Roboactive HWNN (~7.7) + 1 pure

Total: ~3.3 buds

Proof #2

http://www.tf2outpost.com/trade/16312410

Sold for a Power Surge Brain Bucket (~2.5) - old price, but not old enough to call invalid

Total: ~2.5 buds - Outlier?

Proof #3

http://www.tf2outpost.com/trade/15833385

Sold for a PE Brigade (~4) - Last updated price was ~8 months ago. Invalid price?

Total: ~4 buds

Proof #4

http://www.tf2outpost.com/trade/15473765

BOUGHT for ~4 buds pure

Total: 4 pure buds

Currently on Outpost: 1

http://www.tf2outpost.com/search/182595126

Wants 6 buds and bought it for the ~3.3 buds in unusual. Not much interest, but proof is proof.

Conclusion

Finally, I do believe that this is the only suggestion I've countered that was actually somewhat close to the real price of the hat according to sales, but alas, this suggestion was lacking proof. If only he could have done his research, he would've realized his hat is worth more than what he suggested it for. But that's inexperienced backpack.tf suggesters for ya. 2.5 is a quicksale because he wanted a Soldier unusual badly it seemed, and sold very quickly. PE Brigade is a bit outdated, but I have another sold at 4 that shows 4 could be the high-end here.