Well, for your 2 key sellers...

1) Sold 5 days ago

2) Only 3 hours old currently

3) Sold actually, just never checked off the item (check item history)

4) One seller at 3 hours old, another at 6 days.

Could use some more unsolds at 2 possibly?

Also: http://www.tf2outpost.com/trade/15588634 Sold for 2 keys 2 ref only a day ago.

I always look for items to sell to the community market and generaly there are very few items that I can make a profit on

this item sells for about 5-5.70 usd so you receive 2 keys or less ,in my opinion this item is 2 keys flat http://steamcommunity.com/market/listings/440/Vintage%20Half-Zatoichi

2 keys seem to sell pretty fast, as all of those have since sold. The comments show one sale at 2 keys + 2 ref, not quite 2.5 keys but it shows that a range might still be needed here.