In-date, but already needs an update.

Sale 1:

Sold for Secret Muffs (307.5)

No outpost

Seller: https://backpack.tf/profiles/76561198255903931#!/compare/1535155200/1535241600

Buyer: https://backpack.tf/profiles/76561198093495779#!/compare/1534636800/1535241600

https://backpack.tf/item/4717381722

X = 310 (Rounded)

Sale 2:

Sold for Green Energy Flamboyant Flamenco (100) + Green Energy Chill Chullo (130) + Green Confetti HWNN (Suggestion at 27.5) + Terror-Watt Hat to Kill For (Suggestion at 21)

http://www.tf2outpost.com/trade/29637246 - B/O of 375

Seller: https://backpack.tf/profiles/76561198069825031#!/compare/1534291200/1534550400

Buyer: https://backpack.tf/profiles/76561198255903931#!/compare/1534464000/1534550400

https://backpack.tf/item/4717381722

X = 280 (Rounded from 278.5)

Terror-Watt Hat To Kill For:

https://backpack.tf/suggestion/5b9b47b244325a71bf689339

Green Confetti Hat With No Name:

https://backpack.tf/suggestion/5b9b2f49cf6c757056407828

Other Sales:

Untraceable

http://www.tf2outpost.com/trade/29704518 - B/O of 500

https://backpack.tf/profiles/76561198115062041#!/compare/1535155200/1535328000

https://backpack.tf/profiles/76561198041108750#!/compare/1535328000/1535414400

https://backpack.tf/item/5306851495

Sellers:

https://i.imgur.com/vAdlGvt.png

https://backpack.tf/item/5306851495 - 275

https://backpack.tf/item/4973647497 - 400

Sales at:

280

310

2 week seller at 275. Using as the low-end.

From the last suggestion:

https://backpack.tf/suggestion/5b4f3952cf6c75614373d8db - The sale used here is now 4 months old, so it should be fine to ignore it. The sale at 280 was mentioned, but was not used as there was no mini available on the Flamenco at the time. Now that it has re-sold, it should be fine to use.

Going with 275-310.