https://backpack.tf/item/2910745469

https://backpack.tf/profiles/76561198157621024#!/compare/1660953600/1661990400

https://backpack.tf/profiles/76561198105071091#!/compare/1661472000/1661558400

https://gladiator.tf/time-machine?item=Strange+Collector%27s+Professional+Killstreak+Classic&at=2022-08-26T23%3A10%3A00.000Z

Classic + 100 keys for Sunbeams Pyromancer's Mask (562.5), 562.5 - 100 = 462.5 keys, safe to say this would cap at the 400 key buyout.

https://backpack.tf/profiles/76561198105071091#!/compare/1661731200/1661904000

https://backpack.tf/profiles/76561198080276071#!/compare/1661904000/1661990400

https://gladiator.tf/time-machine?item=Strange%20Collector%27s%20Professional%20Killstreak%20Classic&at=2022-08-31T20:16:48.000Z

Seems to have sold alongside the Collector's Gunboats, so would probably call this bulk, buyout was 425 keys

https://marketplace.tf/items/tf2/1098;14;strange

$1666.67/2 = 833.34 keys

I would say that the lower sales and listings from before at ~400 would suggest 833 is a bit high here. Raising conservatively to 400 flat.