Done by me and Tiny Teeny Cat(credit him, he did good job :D)

420 blaze it

Sold for chiroptera venenata rifleman (103), knifestorm wraith wrap (144-156) and duped secret brown bomber (214) = (103 + 150 + 214) * 0.9 = 420 keys

http://backpack.tf/profiles/76561198057621896?time=1428735600 (April 11th)

http://backpack.tf/profiles/76561198057621896?time=1429081200 (April 15th)

Mini for chiroptera rifleman:

Offered with 70 keys for morning glory exquisite rack (155-190) = 172.5 - 70 = 103 keys - offered so no overpay

http://www.tf2outpost.com/trade/25612669

Mini for secret brown bomber:

Offered with beams yellow belt (150) and 10 keys for arcana tough stuff muffs (no recent sales or BOs lower than current price, so using that - 374) = 374 - 150 -10 = 214

Seller before: http://backpack.tf/profiles/76561198026372829?time=1428649200 (April 10th)

Seller after: http://backpack.tf/profiles/76561198026372829?time=1428735600 (April 11th)

sale #2:

Sold for orbiting fire crone's (77.5), electrostatic crone's (173), nuts n bolts crones (30-35), stormy 13th hour brigade helm (94) and duped vintage max's (180) = (77.5 + 173 + 32.5 + 94 + 180) * 0.9 = 501 keys

Buyer before: http://backpack.tf/profiles/76561198040812694?time=1429254000 (April 17th)

Buyer after: http://backpack.tf/profiles/76561198040812694?time=1429513200 (April 20th)

Micro for orb fire crone's:

Sold/offered with 2.5 keys for scorching hermes (80) = 80 - 2.5 = 77.5 keys

Seller's backpack before: http://backpack.tf/profiles/76561198098794519?time=1428908400 (April 13th)

Seller's backpack after: http://backpack.tf/profiles/76561198098794519?time=1429081200 (April 15th)

Mini for electrostatic crone's:

Sold for darkblaze tyrant's helm (192) = 192 * 0.9 = 173 keys

Seller's backpack before: http://backpack.tf/profiles/76561198087204636?time=1428303600 (April 6th)

Seller's backpack after: http://backpack.tf/profiles/76561198087204636?time=1428390000 (April 7th)

Mini for stormy 13th hour brigade helm:

Sold/offered with ~6 keys in sweets for scorching thirst blood (92-108) = 100 - 6 = 94 keys

Seller before: http://backpack.tf/profiles/76561198067893369?time=1424937600 (February 26th)

Seller after: http://backpack.tf/profiles/76561198067893369?time=1425024000 (February 27th)

Mini for duped vintage max's:

http://www.tf2outpost.com/trade/25587157 sold for 180

http://www.tf2outpost.com/trade/24946568 BO was 180

Range is 420-501, Will round to 420-500