Sale #1:

http://www.tf2outpost.com/trade/24834811 - Sold for 1 bud+4 keys+#159 Trencher's Topper (buds were 13 keys at the time)

17 keys+#159 trencher's, no mini for trencher's but would probably be rounded anyway

Sale #2:

http://www.tf2outpost.com/trade/25191901 - Sold for this http://gyazo.com/440a4cbef6c2ba942e57ecc5ae19ffde Flies Noir(1.1), Miam Engineer's Cap(16 keys) and sweets(~1.5 key)

Pricing in keys, http://backpack.tf/vote/id/54cc0672b88d88157a8b4bf1 - Noir was oringinally 12.5 keys-15 keys, Counting Noir as 13.75 keys.

BO:

http://www.tf2outpost.com/trade/25187234 - Seller at 13 keys, Using 13

13+16+1.5=30.5

30.5*0.9=27.45 rounding down to 27 keys

Sale #3:

http://www.tf2outpost.com/trade/25393949 - Sold for scammed or hijacked off, not sure.

Sellers:

http://www.tf2outpost.com/trade/25505043

Support proof:

http://www.tf2outpost.com/trade/24733031 - Quicksold for 1 bud+1 key(buds were 14 keys).

http://backpack.tf/profiles/76561198158033500?time=1426805629 - from a hijacker to someone else... meh whatever not sure what happened there

Minis:

Engineer's Cap:

http://www.tf2outpost.com/trade/25388905 - Sold for C9 Ze-goggles, 4 keys SF Wrangler, S Spec ks diamondback and some cheap genuines. (BO was 20 keys but was sold for over 20 keys). http://gyazo.com/fef2975aa3c6bbb3955bdccd14fad933

BO:

http://www.tf2outpost.com/trade/25332782 - Seller at 16 keys, Using 16 keys

Conclusion:

17 keys sale was long ago(more than 2 months ago) and is close to the quicksell price:

http://www.tf2outpost.com/trade/24733031 - Quicksell price = 15 keys, 17 keys is obviously not the correct price as the quickbuyer was asking 30-50% off(2 keys is not 30-50% off)

Using 27 keys sale!