For Unusuals you can only use Gladiator.tf stats if there are 3 or more sales at the same value, which isn't the case for 10 and 15 keys. You'll need to look through the histories that have sales within the past 3 months using compare links:

https://backpack.tf/item/17426404433

https://backpack.tf/item/17395797034

https://backpack.tf/item/17373604009

https://backpack.tf/item/17358832050

https://backpack.tf/item/17347822372

https://backpack.tf/item/17335188699

https://backpack.tf/item/17330797488

https://backpack.tf/item/17330750919

https://backpack.tf/item/17321476898

https://backpack.tf/item/17309572283

https://backpack.tf/item/17296742442

https://backpack.tf/item/17276237693

https://backpack.tf/item/17273433315

https://backpack.tf/item/17263163741

https://backpack.tf/item/17242356675

https://backpack.tf/item/17238958033

https://backpack.tf/item/17238924846

https://backpack.tf/item/17238066194

https://backpack.tf/item/17238031573

https://backpack.tf/item/17231658316

There's also a Marketplace.tf sale https://marketplace.tf/items/tf2/30836;5;u412

Aug 7, 2026, $42.99/$1.88=22.86 keys ~23 keys (unusable because it's higher than sellers)

Good luck and feel free to ask any questions :)