Going with sales within the last 2 months:

Sale 1:

https://backpack.tf/profiles/76561198025268646#!/compare/1547769600/1547856000

https://backpack.tf/profiles/76561198024867201#!/compare/1547769600/1547856000

QS

Sale 2:

https://backpack.tf/profiles/76561198073070572#!/compare/1545955200/1546732800

https://backpack.tf/profiles/76561198043897422#!/compare/1545955200/1546041600

QS?

Sale 3:

https://backpack.tf/profiles/76561198372525896#!/compare/1548633600/1548720000

https://backpack.tf/profiles/76561198348057478#!/compare/1548633600/1548720000

Bulk

Sale 4:

https://backpack.tf/profiles/76561198348057478#!/compare/1549324800/1549411200

https://backpack.tf/profiles/76561198415180580#!/compare/1549324800/1549411200

Sold for FoD Yeti + ~7.5 keys in sweets

Low.

Sale 5:

https://backpack.tf/profiles/76561198415180580#!/compare/1549324800/1549411200

https://backpack.tf/profiles/76561198043897422#!/compare/1549411200/1549497600

Sold for 20 keys

Sale 6:

https://backpack.tf/profiles/76561198043897422#!/compare/1549497600/1549584000

https://backpack.tf/profiles/76561198116583793#!/compare/1549929600/1550102400

Untrace / bulk

Sale 7:

https://backpack.tf/profiles/76561198334598690#!/compare/1547251200/1547337600

https://backpack.tf/profiles/76561198138135050#!/compare/1547251200/1547510400

Sold for 12 keys

Sale 8:

https://backpack.tf/profiles/76561198226300264#!/compare/1548115200/1548892800

https://backpack.tf/profiles/76561198402152328#!/compare/1548201600/1548288000

Sold for 8 keys

Sale 9:

https://backpack.tf/profiles/76561198402152328#!/compare/1548633600/1548720000

https://backpack.tf/profiles/76561198106511423#!/compare/1548633600/1548720000

Bulk

Sale 10:

https://backpack.tf/profiles/76561198106511423#!/compare/1549324800/1549411200

https://backpack.tf/profiles/76561198348844757#!/compare/1549411200/1549497600

Sold for Blizzardy Helm(17.5) + ~4 keys in sweets

Total is 21.5 keys

Sale 11:

https://backpack.tf/profiles/76561198143892308#!/compare/1545177600/1545264000

https://backpack.tf/profiles/76561198232041512#!/compare/1545177600/1545264000

Bulk

Sale 12:

https://backpack.tf/profiles/76561198232041512#!/compare/1545350400/1545436800

https://backpack.tf/profiles/76561198043897422#!/compare/1545091200/1545436800

Untrace

Sale 13:

https://backpack.tf/profiles/76561198271924256#!/compare/1545782400/1545955200

https://backpack.tf/profiles/76561198160856661#!/compare/1545868800/1545955200

Sold with 12 keys for Isotope Brain Candy FT RL

Prob use there

Sale 14:

https://backpack.tf/profiles/76561198160856661#!/compare/1546387200/1546473600

https://backpack.tf/profiles/76561198335791307#!/compare/1546387200/1546473600

QS

Sale 15:

https://backpack.tf/profiles/76561198335791307#!/compare/1551657600/1551744000

https://backpack.tf/profiles/76561198107203923#!/compare/1551571200/1551744000

Sold for 20 keys

Sale 16:

https://backpack.tf/profiles/76561198140040524#!/compare/1548892800/1548979200

https://backpack.tf/profiles/76561198148511293#!/compare/1548892800/1548979200

Bulk

Sale 17:

https://backpack.tf/profiles/76561198148511293#!/compare/1549929600/1550016000

https://backpack.tf/profiles/76561198302060474#!/compare/1550016000/1550534400

Sold for 13 keys

Sale 18:

https://backpack.tf/profiles/76561198058244665#!/compare/1550707200/1550793600

https://backpack.tf/profiles/76561198086933105#!/compare/1550620800/1550793600

https://backpack.tf/profiles/76561198058244665#!/compare/1550793600/1550880000

https://backpack.tf/profiles/76561198058244665#!/compare/1551484800/1551571200

https://backpack.tf/profiles/76561198417253816#!/compare/1551484800/1551571200

Untrace / tradeback

Sale 19:

https://backpack.tf/profiles/76561198060673163#!/compare/1548892800/1548979200

https://backpack.tf/profiles/76561198050106512#!/compare/1549324800/1549929600

Untrace

Sale 20:

https://backpack.tf/profiles/76561198050106512#!/compare/1549929600/1550361600

https://backpack.tf/profiles/76561198085347196#!/compare/1549929600/1550016000

Untrace

Sale 21:

https://backpack.tf/profiles/76561198085347196#!/compare/1550016000/1550102400

https://backpack.tf/profiles/76561198055050034#!/compare/1550016000/1550102400

QS

Sale 22:

https://backpack.tf/profiles/76561198055050034#!/compare/1550275200/1550448000

https://backpack.tf/profiles/76561198340634356#!/compare/1550188800/1550275200

QS to bot?

Sale 23:

https://backpack.tf/profiles/76561198200475465#!/compare/1549497600/1549584000

https://backpack.tf/profiles/76561198148511293#!/compare/1549497600/1549584000

Bulk

Sale 24:

https://backpack.tf/profiles/76561198148511293#!/compare/1550188800/1550275200

https://backpack.tf/profiles/76561197980761347#!/compare/1550188800/1550275200

Bulk

Sale 25:

https://marketplace.tf/items/1118;5;u3006

$45.00 / $1.64 = 27.44 keys

$25.12 / $1.81 = 13.88 keys

$41.67 / $1.77 = 23.54 keys

$40.00 / $1.75 = 22.86 keys

$39.95 / $1.75 = 22.83 keys

$39.55 / $1.77 = 22.34 keys

$45.00 / $1.8 = 25.00 keys

$60.00 / $1.8 = 33.33 keys

$79.99 / $1.78 = 44.94 keys

Total sales @:

8, 12, 13, 13.88, 20, 20, 21.5, 22.34, 22.86, 23.54, 25, 27.44, 33.33, 44.94 keys

Buyers up to 17 keys,

Sellers down to 23 keys, (23 relisted multiple times)

Taking 20 - 23 keys