I'm currently looking at these so am updating it here. There are often more duplicated ones available than there are clean ones.

[url]http://www.tf2outpost.com/trade/11460319[/url] (Clean.) He took the last offer, "unusual sunbeams merryweather+ sunbeams scotch bonnet" (about 7.5 after counting over-pay). The others simply don't get these great offers so I'm going to call this an outlier.

[url]http://www.tf2outpost.com/trade/11636867[/url] We Spy players know who Stabby is but many traders just offer for this as a dirty Party Phantom. I therefore won't count it since the others receive better offers.

[url]http://www.tf2outpost.com/trade/10468176[/url] (Clean.) "5 buds + 2 bill's (black and white) + 2 keys + sweets" about one month ago. "planets phantom + 4" which is about 5.7 with over-pay, one month ago. He was also asked about six but not actually offered it. 5+$24 (about 5.4). ๖ۣۜDuckyMomoOnQuack also offered six, which he DID have at the time ([url]http://www.tf2outpost.com/trade/11366174[/url]).

[url]http://www.tf2outpost.com/trade/11496092[/url] was bought with "3 buds + black bills + green fetti phantom" plus three or four keys (about 5.3 but that depends on how quickly you wish to sell a Green Confetti Party Phantom) from [url]http://www.tf2outpost.com/trade/11483139[/url].

[url]http://www.tf2outpost.com/trade/11621600[/url] (Clean.) Sold for five and a Strange Festive Bat. I'll call that about 5.9.

[url]http://www.tf2outpost.com/trade/11686272[/url] (Clean and once Woifi's.) was bought with a Secret SnS ([url]http://www.tf2outpost.com/trade/11371987[/url]). Maybe five or six but possibly higher. It's an extremely rare one. Currently this website tells me that it's the only one of its kind so I really don't want to attribute a value to this sale.

[url]http://www.tf2outpost.com/trade/11716640[/url]/[url]http://www.tf2outpost.com/trade/11712284[/url] He just got it but has been offered five buds already. It seems to have bought in a deal with another difficult-to-value hat. [url]http://www.tf2outpost.com/trade/11573677[/url] Again, this is too hard for me.

[url]http://www.tf2outpost.com/trade/11717725[/url] I can say that the last seller just wanted six ([url]http://www.tf2outpost.com/trade/11185818[/url]) and the buyer said that he was looking close to that price, so that sale was somewhere in there.

Six is what they go up to (aside from the super Sunbeams sale), they easily get offered five and non-quick-sell-buying buyers usually add a bit more, so I'm hoping to summarise all of those with a lwer value of 5.5.