VERY few on the market, iunno

http://www.tf2outpost.com/trade/14394330 - Offered 4.66

http://www.tf2outpost.com/trade/9805354 - Sold some at 1 key recently (according to comments)

http://www.tf2outpost.com/trade/14505268 - 1 key, no offers

http://www.tf2outpost.com/trade/14517907 - 4.66 ref

http://www.tf2outpost.com/trade/14463636 - 1 key, no offers

http://www.tf2outpost.com/trade/14424004 - 4.66, some added posts, OP has been offline for some days.

http://www.tf2outpost.com/trade/14504846 - Sold for 1 key

I'd say 1 key for this is becoming more common, and, even though there's a very small market, 4.66 is actually more of an outlier now.

http://steamcommunity.com/market/listings/440/Strange%20Part%3A%20Snipers%20Killed

Also, sales average at ~ $2.90, around 1.2 keys, keys being at $2.40 right now, these things are going up and up.