Don't worry, I got what I need for ze suggestion TO THE COMMENTS! :D

*DISCLAIMER*

Decided to check how this item went on Outpost and from what I can see, it doesn't sell good at 4 keys, many unsold that is. Nearly every buyer on Outpost is paying less, with exception for one. So I think it's time to change it. :)

*UNSOLD*

http://www.tf2outpost.com/trade/8409669 ( Unsold for 3 days at 4 keys )

http://www.tf2outpost.com/trade/8477058 ( Unsold for 2 hours at 4 keys, ofc. won't count it )

http://www.tf2outpost.com/trade/8446865 ( Unsold for 1 day at 4 keys )

http://www.tf2outpost.com/trade/8446019 ( Unsold for 1 day at backpack.tf price high end = 4 keys )

http://www.tf2outpost.com/trade/8119934 ( Unsold for 2 weeks at 4 keys )

http://www.tf2outpost.com/trade/8405064 ( Unsold for 3 days at 4 keys )

Note: http://www.tf2outpost.com/trade/8328422

( Unsold for 6 days at 4 keys, has received about a 4 key offer, but still, not taken and still remains unsold )

*SOLD/BOUGHT/SELLING*

http://www.tf2outpost.com/trade/8465173 ( Managed to sell for 3 keys + 2 ref. It's not in his backpack, so it's most likely sold. He was also the lowest seller on Outpost )

http://www.tf2outpost.com/trade/8437733 ( Bought one for 3 keys )

Note: http://www.tf2outpost.com/trade/8463357

( This one is a bit special, that being said. He wants spreadsheet price and it's currently 3 keys, yet, it remains unsold for the time being. Also that the trade has been up for 20 hours. )

Conclusion: It seems very clear that people are having a hard time selling them for 4 keys. The lowest seller sold his for around 3.5 key and people still manage to buy them for 3 keys.