Suggestion, thanks to unbxrn for the extra history!

Challenge 19, Team F.L.A.M.B.E.S!

51st suggestion, made by Mikey!

Only 1 recent sale.

https://backpack.tf/profiles/76561198000646505#!/compare/1591488000/1591747200

https://backpack.tf/profiles/76561198356460927#!/compare/1591660800/1592092800

16 keys.

Sale 2:

https://backpack.tf/profiles/76561197964171516#!/compare/1586736000/1586822400

https://backpack.tf/profiles/76561198004952793#!/compare/1586822400/1586908800

sold for 15 keys

Sale 2:

https://backpack.tf/profiles/76561198004952793#!/compare/1587340800/1587427200

https://backpack.tf/profiles/76561198068546927#!/compare/1587340800/1587427200

sold for 19 keys

sale 3:

https://backpack.tf/profiles/76561198068546927#!/compare/1587513600/1587600000

https://backpack.tf/profiles/76561198123224716#!/compare/1587513600/1587600000

Bulk

sale 4:

https://backpack.tf/profiles/76561198123224716#!/compare/1587859200/1587945600

https://backpack.tf/profiles/76561198089791817#!/compare/1587772800/1587859200

Sold for 15 keys

sale 5:

https://backpack.tf/profiles/76561198089791817#!/compare/1588118400/1588723200

https://backpack.tf/profiles/76561198283256881#!/compare/1589414400/1589500800

Untrace

Sale 6:

https://backpack.tf/profiles/76561198283256881#!/compare/1589414400/1589500800

https://backpack.tf/profiles/76561198140935870#!/compare/1589414400/1589500800

Sold with 3 keys for HG Pith

use there

Sale 7:

https://backpack.tf/profiles/76561198140935870#!/compare/1589500800/1589760000

https://backpack.tf/profiles/76561198398579602#!/compare/1589414400/1589500800

untrace

sale 8:

https://backpack.tf/profiles/76561198398579602#!/compare/1589414400/1589500800

https://backpack.tf/profiles/76561198262024917#!/compare/1589414400/1589500800

Sold for ~14 keys

sale 9:

https://backpack.tf/profiles/76561198262024917#!/compare/1590192000/1590537600

https://backpack.tf/profiles/76561198797465027#!/compare/1590019200/1590192000

Sold with ~2 keys in sweets for Max Head(~18)

Total is 16 keys

Sale 10:

https://backpack.tf/profiles/76561198797465027#!/compare/1590019200/1590192000

https://backpack.tf/profiles/76561198186201090#!/compare/1590105600/1590192000

Untrace

sale 11:

https://backpack.tf/profiles/76561198851597200#!/compare/1590537600/1590624000

https://backpack.tf/profiles/76561198137944431#!/compare/1590537600/1590624000

Sold for 16 keys (keys used to buy spelled degreaser)

Total sales @:

14, 15, 15, 16, 16, 16, 19 keys

buyers up to 13 keys,

calling 14 low,

19 high,

taking 15 - 16 keys.