The Sale:

Sold for 7 keys + 42 ref

Seller: https://backpack.tf/profiles/76561198305494036#!/compare/1587254400/1587340800

Buyer: https://backpack.tf/profiles/76561198160856661#!/compare/1587254400/1587340800

https://backpack.tf/item/7084317091

https://i.imgur.com/GehaRZy.png - bot.tf confirms

8 keys

Marketplace Sales:

https://marketplace.tf/items/tf2/30326;5;u57

$19, March 31st

$20, April 20th

No snapshots available

https://backpack.tf/item/5509695226 - March 31st

http://manic.tf/keyprice?at=2020-03-31&price=19 - $19 / $1.69 = 11.24 keys

https://backpack.tf/item/7084317091 - Most likely the April 20th sale (Torb > Rawz)

http://manic.tf/keyprice?at=2020-04-20&price=20 - $20 / $1.79 = 11.17 keys

Other Sales:

https://backpack.tf/item/7956330852 (#1)

https://backpack.tf/item/7084317091 (#2 & #3, excluded gambling)

https://backpack.tf/item/5509695226 - marketplace/gambling or otherwise unusable.

#1

Untraceable

https://backpack.tf/profiles/76561198311498888#!/compare/1587340800/1587427200

https://backpack.tf/profiles/76561198078759053#!/compare/1586304000/1587859200

#2

Untraceable

https://backpack.tf/profiles/76561198337734785#!/compare/1586131200/1586217600

https://backpack.tf/profiles/76561198302201202#!/compare/1586131200/1586217600

#3

Untraceable

https://backpack.tf/profiles/76561198278721648#!/compare/1587254400/1587340800

https://backpack.tf/profiles/76561198305494036#!/compare/1587254400/1587340800

https://i.imgur.com/GehaRZy.png - labelled as 6 keys + 42 ref

9 ref matches

Sellers:

https://i.imgur.com/gR3SrYY.png

https://backpack.tf/item/7957618705 - 11 keys

https://backpack.tf/item/7955842836 - ~11.8 keys

Sales at:

8

11 (2x)

8 quicksold, but the seller at 11 is 2 months old, and the bot that quicksold for 8 supposedly got one for 7. Keeping 8.

Taking 8-11.