The price needs a little update. Easy to find this item at 4 keys, or even lower. Nobody is buying it at 4.5 keys anymore. Proof is below.

Sellers:

http://www.tf2outpost.com/trade/8746329 - 4.5 keys, unsold, 2 weeks

http://www.tf2outpost.com/trade/9036928 - 4.5 keys, unsold, 6 days

http://www.tf2outpost.com/trade/9109673 - 4.5 keys, unsold, 3 days

http://www.tf2outpost.com/trade/9176124 - 4.5 keys, 11 hours, no takers

http://www.tf2outpost.com/trade/9164302 - 4 keys + 1 ref (4.25 keys), 22 hours, no takers

http://www.tf2outpost.com/trade/8830916 - 4 keys, unsold, 2 weeks (probably the price was changed not so long time ago)

http://www.tf2outpost.com/trade/8743639 - 4 keys, unsold, 2 weeks (probably the price was changed not so long time ago)

http://www.tf2outpost.com/trade/9074848 - 4 keys, unsold, 4 days

http://www.tf2outpost.com/trade/9107588 - 4 keys, unsold, 3 days

http://www.tf2outpost.com/trade/9163325 - 4 keys, 22 hours, no takers

http://www.tf2outpost.com/trade/9173003 - 4 keys, 15 hours, no takers

http://www.tf2outpost.com/trade/9188112 - 4 keys, still new trade

http://www.tf2outpost.com/trade/8916134 - 4 keys, sold

http://www.tf2outpost.com/trade/9036740 - 4 keys, sold

http://www.tf2outpost.com/trade/9173916 - 4 keys, sold

http://www.tf2outpost.com/trade/9136757 - 3.5 keys, 2 sold, 2 in stock (Edited: right now he's selling it at 3 keys, probably a quckselling)

Also TF2Warehouse is selling it for 58940 credits (~4.5 keys). Stock is full

http://www.tf2wh.com/item.php?id=970;11;4a1eddb070edb7c80bdf6dc1bc058047

Buyers:

http://www.tf2outpost.com/trade/9177578 - 3 keys

http://www.tf2outpost.com/trade/9065036 - 12.66 ref (~3 keys)

http://www.tf2outpost.com/trade/8935288 - 2.5 keys

http://www.tf2outpost.com/trade/9034549 - 2 keys + 1 ref (~2.25 keys)

http://www.tf2outpost.com/trade/8762286 - 2 keys

http://www.tf2outpost.com/trade/8046533 - 2 keys

http://www.tf2outpost.com/trade/8245936 - 4 keys, inactive trade with a disabled autobump, don't have keys in his BP