You have a lot of sellers, but you need actual sales to price an item.

Trade.tf at a solid 4 keys. 4 keys in the classifieds. down vote

http://steamcommunity.com/market/listings/440/Strange%20Festive%20Crusader%27s%20Crossbow unstable but it could obtain for 10$ easily ~ 4-4.5 keys

http://i.imgur.com/BDaU20p.jpg 2 in classifieds listed at 4 keys

http://www.tf2outpost.com/trade/16602381 4 keys

tf2wh priced at 2.5 keys ..

4-5 keys would be more accurate

I couldn't even sell mine for 4 keys 2 days ago, so I think at the very least 4-5 is sufficient. Item is not very popular

I think 6 for now. All competitive medics will likely want to play with these (similar to the festive strange medigun.

The price will likely go up, as well, but I think 5-6 is fair, without trying to predict the future.

List of solds here: http://backpack.tf/vote/id/52b862d74dd7b8010f8b456c

But with all these current sellers, 5 flat seems better.

http://www.tf2outpost.com/trade/16641585

http://www.tf2outpost.com/trade/16590212

http://www.tf2outpost.com/trade/16561571

http://www.tf2outpost.com/trade/16614397

http://www.tf2outpost.com/trade/16622943

http://www.tf2outpost.com/trade/16566359

http://www.tf2outpost.com/trade/16534735

http://www.tf2outpost.com/trade/16545097

http://www.tf2outpost.com/trade/16638923

http://www.tf2outpost.com/trade/16629320

http://www.tf2outpost.com/trade/16597835

http://www.tf2outpost.com/trade/16609444

http://www.tf2outpost.com/trade/16644458

http://www.tf2outpost.com/trade/16643295