The last link was not sold for pure, it was sold for the blizzardy festive tree offer, and may or may not have included sweets. The festive tree isn't in the backpack because it was resold (item history shows the person who bought the virus doctor passing it to the person who sold the virus doctor, then onward)

http://www.tf2outpost.com/trade/17968544

Edit: This does still support a price right near 3 buds, given unusual overpay, depending on the sweets. Happily, the tree has been updated very recently, so it's fresh for reference.