Credit to Admiral Pete, Lemons, and Link for being very thorough.

Admiral Pete:

Item 1 - Scrap TF Auction

= 55 Keys - exclude

Item 2 - Past 3 Month on Marketplace TF

109.99/1.68 = 65 Keys - exclude, due to being a key above buy order

Item 3 - History of First Listing

https://backpack.tf/profiles/76561198249548030#!/compare/1700265600/1700438400

Seems to either have obtained through Gambling or a mix of Items, either way, unavailable

Item 4 - History of Second Listing

https://backpack.tf/profiles/76561198191854982#!/compare/1704844800/1704931200

Gambled over 200 Keys worth of Items to obtain, untraceable

https://backpack.tf/profiles/76561199161916038#!/compare/1704844800/1704931200

Also gambled away almost 500 items for 1600, untraceable

https://backpack.tf/profiles/76561198390579099#!/compare/1703980800/1704067200

https://backpack.tf/profiles/76561198390579099#!/compare/1703894400/1703980800

Bought for a mix on Items, then gambled away again, untraceable

Item 5 - Hardstyle

https://backpack.tf/profiles/76561198091840184#!/compare/1704412800/1704499200

For some reason Keys don't show up in his backpack but he gave screenshots to prove a purchase of 68 Keys - exclude, due to 4 keys above buy order.

https://photos.onedrive.com/share/43E4BAA932ECB949!27158?cid=43E4BAA932ECB949&resId=43E4BAA932ECB949!27158&authkey=!ADvmZurvPaEIWD8&ithint=photo&e=YCmuQU

https://gyazo.com/4fe29d07ac526fca083bdb8fce34e938

Mine:

Item 6

https://backpack.tf/item/10936299043

https://backpack.tf/profiles/76561198191854982#!/compare/1705276800/1705363200

https://backpack.tf/profiles/76561198162339320#!/compare/1705276800/1705363200

Bulk

Item 7

https://backpack.tf/item/10936299043

https://backpack.tf/profiles/76561198162339320#!/compare/1707004800/1707177600

https://backpack.tf/profiles/76561198199244659#!/compare/1707177600/1707264000

Item 8

https://backpack.tf/item/10936299043

https://backpack.tf/profiles/76561198199244659#!/compare/1707264000/1707350400

https://backpack.tf/profiles/76561198239575462#!/compare/1706745600/1707350400

70 Keys

Item 9

https://backpack.tf/item/10936299043

https://backpack.tf/profiles/76561198064724507#!/compare/1707436800/1707523200

https://backpack.tf/profiles/76561198239575462#!/compare/1707523200/1707609600

I paid 150 keys for the Purple Energy California Cap and the Strange Sunbeams Big Chief ---75 keys

Sales:

55 - exclude

65 - exclude

68 - exclude

70 -

75

Since, the other sales are practically quicksell. I'll be going with a range of 70 - 75 keys or an average of 72.5 keys flat!

Feedback welcome! Thanks!