Sale 1

Sold for $499;

https://marketplace.tf/items/tf2/30897;5;u46

https://backpack.tf/item/6286643233

Keys currently at $1.91

499/1.91=261

Sale 2

Sold for a Stormy Storm Soldier's Stash (107.5 Keys) + 85 Keys + Nuts n' Bolts Le Party Phantom (19.5 Keys) + Blizzardy Storm Reggaelator (16.5 Keys)

https://backpack.tf/profiles/76561198050582650#!/compare/1590192000/1590278400

https://steamuserimages-a.akamaihd.net/ugc/1244631308528914686/5C076110D1F30E214EED30B91B0978BC109EA05B/

107.5 + 85 + 19.5 + 16.5 = 228.5, which can be rounded to 230 Keys.

https://backpack.tf/suggestion/5ef110d35ea62150cc13ba46 - Stash suggestion at 107.5 Keys

https://backpack.tf/suggestion/5ef11bcb53c2fc172f2eb132 - Phantom suggestion at 19.5 Keys

https://backpack.tf/suggestion/5ecd6aaffe99a01c3f658a0a - Reggaelator suggesion at 16.5 Keys

Taking 230 - 260 as a nice round figure