I will give you links to some of them.
http://backpack.tf/classifieds?item=Bot Dogger&quality=5&tradable=1&craftable=1&australium=-1&particle=29
http://backpack.tf/classifieds?item=Hot Dogger&quality=5&tradable=1&craftable=1&australium=-1&particle=35
http://backpack.tf/classifieds?item=Hot Dogger&quality=5&tradable=1&craftable=1&australium=-1&particle=34
these are the cheapest ones that have sales, but if you want links to the cheapest that are not for sale, go here
http://backpack.tf/unusual/Bot Dogger
http://backpack.tf/unusual/Hot Dogger
Im pretty sure there is no cheaper unusuals than these ones
