Sales:

http://www.tf2outpost.com/trade/24932958 - Sold for 26 keys according to history, Sold 17 days ago, due to buds dropping and sale being in keys ill use keys as the currency.

http://www.tf2outpost.com/trade/22878371 - Sold for 3 buds but is very old... seems like he forgot to close the trade because he already sold it.

http://www.tf2outpost.com/trade/25340786 - Sold for 28 keys

http://www.tf2outpost.com/trade/25339319 - Sold for 27 keys

http://www.tf2outpost.com/trade/24525686 - Sold for 3 buds(buds were 15 keys that time so this is obviously outlier, at least for this time).

None on SCM so can't use as supported proof...