Sellers:

http://www.tf2outpost.com/trade/17988098

4 ref sold from last suggestion

http://www.tf2outpost.com/trade/18132937

3.33 and 3.11 offer (owner accepted both but ended up selling to 3.11)

http://www.tf2outpost.com/trade/18095921

Guy from above bought for 3.33 here

http://www.tf2outpost.com/trade/18221028

3 ref unsold (4 hours)

http://backpack.tf/profiles/76561198102092169

4.22 unsold (17 hours)

Buyers:

3 refined

http://www.tf2outpost.com/trade/18176046

http://www.tf2outpost.com/trade/18092700

http://www.tf2outpost.com/trade/18191599

http://www.tf2outpost.com/trade/17965558

http://www.tf2outpost.com/trade/17029550

http://www.tf2outpost.com/trade/18149120

SCM:

http://steamcommunity.com/market/listings/440/Strange%20Rust%20Botkiller%20Sniper%20Rifle%20Mk.I

Graph levels out on a low end of 1.4-1.5 which nets the sell about ~3.66 after fees

COnclusion:

Shouldnt have stopped at 3 ref. Price should probably be higher than Im suggesting but I dont feel like argueing on this one.