straightforward

sold with haunted ghosts neckwear for death by disco hellmet

https://backpack.tf/profiles/76561198131633162#!/compare/1556409600/1556582400

using there (even if i used it here, neckwear mini is at 34 while death by disco hellmet mini is at 57.5 [57.5 - 34 = 23.5 rounding to 24, which is lower than the buyer])

1 marketplace sale

https://marketplace.tf/items/30897;5;u62

69.99 usd on june 16 (69.99 / 1.84 = 38.03 rounding to 38 keys)

buyers for the shellmet

https://gyazo.com/1092774448c9bfab9e4fe57f7ea97e91

buyer at 25, and sale at 38, taking 38 keys flat here.