good example.

SALE 1

sold for logo fly guy

https://backpack.tf/profiles/76561198123814820#!/compare/1562803200/1562889600

https://backpack.tf/profiles/76561198208677149#!/compare/1562544000/1562889600

fly guy indate

SALE 2

sold for subatomic head full of hot air

https://backpack.tf/profiles/76561198208677149#!/compare/1562889600/1563148800

https://backpack.tf/profiles/76561198067764019#!/compare/1562803200/1562889600

head full of hot air is outdated @ 5 months, however outdated price is in the range, and judging by classifieds it would fit, or be lower than buyers.

SALE 3

sold for 9 keys + 29 refined

https://backpack.tf/profiles/76561198067764019#!/compare/1562803200/1562889600

would round up to 10 keys

SALE 4

sold for 7 keys?

https://backpack.tf/profiles/76561198312583107#!/compare/1557446400/1557705600

https://backpack.tf/profiles/76561198210678091#!/compare/1557619200/1557705600

SALE 5

sold with 2 keys for searing puffy polar cap

https://backpack.tf/profiles/76561198210678091#!/compare/1557705600/1557792000

https://backpack.tf/profiles/76561198272353085#!/compare/1557705600/1557792000

polar cap is outdated @ 9 months, due to the polar cap having less usable sales, using this sale there.

SALE 6

sold for 9 keys + 38 refined + vintage ambassador

https://backpack.tf/profiles/76561198272353085#!/compare/1557792000/1557964800

https://backpack.tf/profiles/76561198043914474#!/compare/1557878400/1557964800

would round up to 10 keys

SALE 7

unknown

https://backpack.tf/profiles/76561198337734785#!/compare/1558828800/1558915200

https://backpack.tf/profiles/76561198296550363#!/compare/1558828800/1559952000

b/o was 11

https://bot.tf/stats/listings/4JX58K7M

SALE 8

sold for 11 keys

https://backpack.tf/profiles/76561198065311905#!/compare/1563408000/1563494400

https://backpack.tf/profiles/76561198154495510#!/compare/1563408000/1563494400

SALE 9

sold for 13 keys

https://backpack.tf/profiles/76561198335791307#!/compare/1558915200/1559001600

https://backpack.tf/profiles/76561198102861548#!/compare/1558915200/1559001600

SALE 10

sold for 9 keys + 24 refined

https://backpack.tf/profiles/76561198080797179#!/compare/1562716800/1563321600

rounds down to 9 keys

SALE 11

unknown - nothing seems to match

https://backpack.tf/profiles/76561198021055079#!/compare/1556236800/1556323200

https://backpack.tf/profiles/76561198073542318#!/compare/1556064000/1559174400

2 marketplace sales

34 on may 11 (34 / 1.79 = 18.99 rounding to 19 keys)

23.99 on june 1 (23.99 / 1.82 = 13.18 rounding to 13 keys)

https://marketplace.tf/items/tf2/31010;5;u112

classifieds at the time of making this suggestion.

https://gyazo.com/9ebb540adbd8ab973bd8827a35a1f9db

sales at 7, 9, 10, 10, 11, possibly 11, 11, and 13. marketplace sales at 13 and 19. 7 and 9 are obviously low due to buyers. 19 is obviously high due to sellers and quite a few sales at lower. taking a range of 10-13 keys here.