Proof:

Sellers:

http://backpack.tf/classifieds/search/6009/6/0 - I can't see anything under 1.8

http://www.tf2outpost.com/trade/9452823 - Got offered Vintage Caber which was 2 – 2.75 at the time (I still consider item overpay but that still makes it around 2)

http://www.tf2outpost.com/trade/9371883 - Got offered 1 key + 4.88, 1 key + 3 and 1 key + 3.33, he declined all

http://www.tf2outpost.com/trade/9803318 - I can see an add but idk if he really sold it

http://www.tf2outpost.com/trade/9803318 - I can see an add but idk if he really sold it

http://www.tf2outpost.com/trade/9803318 - Was offered pink All-Father (I still consider item overpay but that's still 2 or a bit more)

http://www.tf2outpost.com/trade/10257726 - I can see some adds and again Vintage Caber offer and an offer of 5 keys + 1 ref for Headshot + Buildings which is basically 2 keys for buildings

http://www.tf2outpost.com/trade/10296387 - Someone wrote he'll take 2, idk if it happened

http://www.tf2outpost.com/trade/10672203 - I can see 2 adds, idk it happened

Buyers:

http://www.tf2outpost.com/trade/10495605 - 1 key + 2 ref is what he wants which is a quicksell but also close to lower end and nothing for a week and it's also bumped, idk if a lot but it is

http://www.tf2outpost.com/trade/10241930 - 1 key + 2 ref which is almost low end and nothing for 6 days

http://www.tf2outpost.com/trade/10241930 - 7 ref which is almost low end and if you scroll down you can see nothing within like 2 weeks or more

http://www.tf2outpost.com/trade/10241930 - 1 key + 2.33 which is almost low end and nothing for 3 weeks except someone who wants 2 keys

http://www.tf2outpost.com/trade/10241930 - 1 key + 2.33 which is almost low end and I all I can see is someone who wanted 1 key + 4 ref and the owner said he can do 1 key + 3 ref but he already sold it, idk for how much

http://www.tf2outpost.com/trade/10623351 - 8 ref which is low end, I can see few adds but I looked at his bp and he has like 10000 strange part but I couldn't find any Buildings Destroyed

Some of the offers are 2 or 3 weeks old, I tried to find newest but it's hard to find anything that isn't 1 key + 2 ref or lower which is a complete lowball, some do sell for that price and it's a quicksell which shouldn't affect price and some are unsold for a long time

But you need to remember it's hard to get a decent offer on high value items and in the end many also manage to sell for 2 keys

I do have 1 but I don't make this suggestion to raise it's price so I can sell and if there's anything wrong in range or proofs please tell me and if too many things are wrong I'll close or re-suggest