Purple thing

Sale 1:

https://marketplace.tf/items/30081;5;u72/Roboactive%20Tsarboosh

= $75.09 / $1.75

= 42.90...

~ 43 keys

Sale 2:

https://backpack.tf/profiles/76561198261509772#!/compare/1549152000/1549411200

https://backpack.tf/profiles/76561197994697258#!/compare/1549065600/1549152000

Seems bulky

Sale 3:

https://backpack.tf/profiles/76561197994697258#!/compare/1549238400/1549324800

https://backpack.tf/profiles/76561198843729039#!/compare/1549152000/1549324800

= Green Energy Battle Boonie (34 keys - indate) + 1 key + Strange Professional Killstreak Holiday Punch (2 keys + 30 ref = 2.68 keys) + Strange Professional Killstreak Carbonado Botkiller Wrench Mk.I (6 keys) + Strange Professional Killstreak Gold Botkiller Scattergun Mk.II (10 keys + 36.22 ref = 10.82 keys)

= 54.5

~ 55 keys

Summary: 43, 55

Conclusion: Going for a 43-55 key range, based on Sales 1 & 3.