I got this thing as part of a trade and so I was looking up the price on outpost to see how it is going for and i found that the price is significantly different from what this site is suggesting. this was when i almost sold it to an obvious reseller who added me very quickly for 3.33 ref. Anyway, some links..

Buying:

1 key

http://www.tf2outpost.com/trade/9106632 - 5 days old and offered mann mint painted one if + 2 ref

http://www.tf2outpost.com/trade/8128531 (looking for quicksells?) - has 1 in bp but appears to still be buying

http://www.tf2outpost.com/trade/8607039 - 1 add for 1 key

http://www.tf2outpost.com/trade/9213326 - 1 add for 1 key

3 ref to 1 key

http://www.tf2outpost.com/trade/8893389 - 3 ref for 2 weeks no offers

http://www.tf2outpost.com/trade/9019566 - 3.77 for 1 week unsuccessful

I don't think it's really necessary to include seller trades here but suffice to say that there are none below 1 key and there are only 3 pages on outpost with half of them painted. there are even sellers as high as 4 keys!

edit: also, community market is averaging $2.87 which is more than 1 key.