Proof below. 4 month-old price.

Sales:

http://www.tf2outpost.com/trade/17452901

-sold for 1 bud+10 keys=~1.5 buds in a day quicksell

http://www.tf2outpost.com/trade/16952022

-stash (no trade)+possible sweets bought g. fetti pampered

http://www.tf2outpost.com/trade/17429135

-wanted 2 buds

-seems to have sold for blizz phantom (slightly outdated): http://www.tf2outpost.com/trade/17431960

-~2 buds

http://www.tf2outpost.com/trade/17020064

-wanted 2 buds

-seems to have sold for bubbling modest: http://www.tf2outpost.com/trade/17066495

-which is clearly over the price of 2 buds

http://www.tf2outpost.com/trade/16973991

-sold for 1 bud+9 keys=~1.5 buds in a day again quicksell

http://www.tf2outpost.com/trade/16897371

-seems to have sold for peace kabuto: http://www.tf2outpost.com/trade/16887060

-~1.8 buds

Current trades:

http://www.tf2outpost.com/trade/14308550

-recent notable offers:

1 bud+black bills+4 keys+12.66 ref+festive knife=1.8

stormy cowl (slightly outdated)=2.1 but can't use since outdated

http://www.tf2outpost.com/trade/14308550

-wants ~1.8 buds, new trade

-notable offers:

none

http://www.tf2outpost.com/trade/15755431

-notable offers:

2 buds

stormy cowl+sweets from same guy but cowl is outdated and doesn't fit in with other proof

Sales: 1.5, 1.5, 1.8, 2, 2

1.8-2 seems to be the best range here. 1.8 is from a sale, a new trade's price and an offer. 2 is from 2 sales and an offer. 1.5 is clearly too low, both sold extremely quickly for pure and offers around there have been immediately declined.