Here goes this one.

Sale 1: Sold for 58 keys

https://backpack.tf/profiles/76561198105324926#!/compare/1566691200/1566777600

https://backpack.tf/profiles/76561198342161127#!/compare/1566691200/1566777600

Buyout was also 58 keys.

https://bot.tf/stats/listings/MQ9W6W63

Sale 2: Sold for pe whoopee cap + unique legendary lid

https://backpack.tf/profiles/76561198105324926#!/compare/1566777600/1568160000

https://backpack.tf/profiles/76561198276175369#!/compare/1566604800/1569628800

Whoopee cap is outdated.

35 + 1.35 = 36.35 rounding to 36 keys

Quick mini for whoopee cap:

Sellers from 32.45 to 35 (3 of which are clean)

https://gyazo.com/74635c30480c8667e1d9569adddb972b

Taking 35 for the sake of the suggestion (although I know it would be high).

Sale 3: Bulk

https://backpack.tf/profiles/76561198298945784#!/compare/1569283200/1569369600

https://backpack.tf/profiles/76561198114402400#!/compare/1569283200/1569369600

Sale 4: Unknown

https://backpack.tf/profiles/76561198237929718#!/compare/1569196800/1569283200

https://backpack.tf/profiles/76561198298945784#!/compare/1569196800/1569283200

Sale 5: Sold for ge towering pillar + 3 keys

https://backpack.tf/profiles/76561198132741569#!/compare/1569110400/1569196800

https://backpack.tf/profiles/76561198237929718#!/compare/1569110400/1569196800

Pillar is outdated.

45.5 + 3 = 48.5 rounding to 49 keys

No buyout found.

Mini for pillar:

https://backpack.tf/suggestion/5da1fcaed381724f013c1333

Classifieds:

https://gyazo.com/177b7bee58c67b8d13f62d269ac0a7ca

Conclusion: Sales at 36, 49, and 58.

36 is low due to buyers at 39.

Taking 49-58 keys.