7 months old -- needs a price bump at minimum, but I believe that the current range is a bit outdated.

Unfortunately there are only two open trades and a few trades recent enough to fit in this price suggestion.

Open Trades

http://www.tf2outpost.com/trade/14315165 - 5 bud buyout, open for only 2 weeks so far. Offered unusuals about 4.5 that the owner didn't take.

http://www.tf2outpost.com/trade/14311483 - Also a 5 bud buyout, apparently someone had an interest but they couldn't work it out.

Closed Trades

http://www.tf2outpost.com/trade/13972559 - Buyout of 5 buds was apparently met. (1 month old)

http://www.tf2outpost.com/trade/9806814 - Buyout of 5 buds was also apparently met. (5 months old but still more recent than the 7 month old price)

Overall there isn't a whole lot of demand for these unusuals, so the proof is scarce. However it's shown that the owner(s) of these unusuals have turned down unusual offers under 5, and that a buyout of 5 can be met.