On outpost, many of these paints sell easily for 7-8 ref.

***PROOF***

http://www.tf2outpost.com/trade/8479240 Sold a couple for 2 keys

http://www.tf2outpost.com/trade/9200410 Sold out for 2 keys each

http://www.tf2outpost.com/trade/9032884 Selling for 2 keys each

http://www.tf2outpost.com/trade/9039265 Selling for 2 keys, offered 7 ref

http://www.tf2outpost.com/trade/9259224 Selling for 7 ref

http://www.tf2outpost.com/trade/9238851 Selling for 2 keys

http://www.tf2outpost.com/trade/9036872 Sold out for 7 ref

http://www.tf2outpost.com/trade/9258577 Offered 7.66 ref

http://www.tf2outpost.com/trade/3120046 Sold for 7 ref

http://www.tf2outpost.com/trade/9233632 Selling for 7 ref

I haven't found many other sellers at 6 ref, so I think this price should go up.

More proof will be added as needed, but feel free to add more proof/counter proof below!