Second suggestion, hope this goes good.

A large majority are painted, making the market quite limited.

Classifieds at the time of this suggestion

http://backpack.tf/classifieds/?item=The%20Essential%20Accessories&quality=6&tradable=1&craftable=1

1 @ 16.33 ref

1 @ 1 key + 8 ref

1 @ 17 ref

12 @ 2 keys (some painted)

8 @ 2.11 keys (some painted)

1 @ 2.18 keys (painted)

3 @ 2.22 keys (some painted)

1 @ 2.24 keys (painted)

2 @ 2.33 keys (painted)

1 @ 20 ref (painted)

Rest are 2.44 keys or more

Sellers at 16.66 ref

http://www.tf2outpost.com/trade/23183156

Sellers at 1 key + 8 ref

http://www.tf2outpost.com/trade/21729790

Sellers at 2 keys

http://www.tf2outpost.com/trade/23223119

http://www.tf2outpost.com/trade/23241733

http://www.tf2outpost.com/trade/20865823

http://www.tf2outpost.com/trade/23093167

http://www.tf2outpost.com/trade/23243479

http://www.tf2outpost.com/trade/23251138

http://www.tf2outpost.com/trade/23215545

http://www.tf2outpost.com/trade/23242448

http://www.tf2outpost.com/trade/23101919

http://www.tf2outpost.com/trade/23203616

http://www.tf2outpost.com/trade/23200634

http://www.tf2outpost.com/trade/23152460

Unsolds at 2 keys + 1 ref

http://www.tf2outpost.com/trade/23075769

http://www.tf2outpost.com/trade/22943711

http://www.tf2outpost.com/trade/23202334 Says BP.TF price, most likely highest range

Unsolds at 2 keys + 2 ref

http://www.tf2outpost.com/trade/23180693

http://www.tf2outpost.com/trade/22820978

http://www.tf2outpost.com/trade/23106417

Unsolds at 2 keys + 5 ref

http://www.tf2outpost.com/trade/23081816

Conclusion

2 keys is very common and anything above seems to not sell.