Hi

I am not very good at suggesting prices,but I´ll try

3 sales on marketplace.tf during last 3 months:

https://marketplace.tf/items/tf2/31154;5;u3053

-2 of them at 39,99/1,81$(key price)=22,09~rounding to 22 keys

-1 of them at 49,99/1,81$(key price)=27,61~rounding to 28 keys (high value)

I bought one for 25 keys

https://backpack.tf/profiles/76561198083134207#!/compare/1628121600/1628208000 (backpack of the seller)

One sale of 20 keys (low value)

https://backpack.tf/item/9667217065

https://backpack.tf/profiles/76561199059160806#!/compare/1624320000/1624406400

This sale seems to be sold as a set for other items(?)

https://backpack.tf/profiles/76561198109141608#!/compare/1620345600/1620518400

This one seems to be sold for 10 keys

https://backpack.tf/profiles/76561h198970722371#!/compare/1622764800/1622851200

Which is an outlier due to the buyers are higher than this sale

And there are 2 mores sales,but they are out of date and are untrackeable

https://backpack.tf/item/9579332139

https://backpack.tf/item/9556195025

In conclusion i think a range of 20-28 seems good.

Have a nice day