Re-suggesting.

Sale 1:

Sold for 26 keys

Seller: https://backpack.tf/profiles/76561198310144372#!/compare/1522368000/1522454400

Buyer: https://backpack.tf/profiles/76561198317658037#!/compare/1522368000/1522540800

Bot.tf confirms: https://i.imgur.com/dvJ8LOF.png

X = 26

Sale 2:

Sold for 24 keys

Seller: https://backpack.tf/profiles/76561198280678753#!/compare/1523664000/1523750400

Buyer: https://backpack.tf/profiles/76561198073966347#!/compare/1514246400/1523750400

X = 24

Sale 3:

Sold to a bot for 24 keys + 10 ref

Seller: https://backpack.tf/profiles/76561198145395354#!/compare/1524700800/1525046400

Buyer: https://backpack.tf/profiles/76561198304138933#!/compare/1524960000/1525046400

Bot.tf confirms: https://i.imgur.com/dvJ8LOF.png

X = 24

Sale 4:

Sold to a quickbuyer for 23 keys + ~1 key in metal

Seller: https://backpack.tf/profiles/76561198061902266#!/compare/1523059200/1523145600

Buyer: https://backpack.tf/profiles/76561198155320889#!/compare/1523059200/1523145600

X = 24

Sale 5:

Sold to a bot for 23 keys + 22 ref

Seller: https://backpack.tf/profiles/76561198073553007#!/compare/1520985600/1521072000

Buyer: https://backpack.tf/profiles/76561198310144372#!/compare/1520985600/1521072000

Bot.tf confirms: https://i.imgur.com/dvJ8LOF.png

X = 24

Sale 6:

Sold to a bot for 22 keys + 13 ref

Seller: https://backpack.tf/profiles/76561198046580198#!/compare/1526601600/1526688000

Buyer: https://backpack.tf/profiles/76561198305676157#!/compare/1526601600/1526688000

Bot.tf confirms: https://i.imgur.com/dvJ8LOF.png

X = 22

Sale 7:

Sold to a bot for 22 keys + 13 ref

Seller: https://backpack.tf/profiles/76561198068331753#!/compare/1527033600/1527984000

Buyer: https://backpack.tf/profiles/76561198830746853#!/compare/1527897600/1527984000

Bot.tf confirms: https://i.imgur.com/dvJ8LOF.png

X = 22

Sale 8:

Sold to a bot for 22 keys + 13 ref

https://backpack.tf/profiles/76561198128838220#!/compare/1528243200/1528329600

https://backpack.tf/profiles/76561198305676157#!/compare/1528243200/1528329600

Bot.tf confirms: https://i.imgur.com/iYpfxPE.png

X = 22

Sale 9:

Sold for DBD Old Guadalajara + metal

Seller: https://backpack.tf/profiles/76561198305676157#!/compare/1526688000/1526774400

Buyer: https://backpack.tf/profiles/76561198331167728#!/compare/1526688000/1526774400

https://i.imgur.com/dvJ8LOF.png – B/O of 24, according to bot.tf

I’m certain keys were involved, but just aren’t visible in the compare links. Excluding.

Sale 10:

Bulk for keys

Seller: https://backpack.tf/profiles/76561198425834534#!/compare/1527379200/1527552000

Buyer: https://backpack.tf/profiles/76561198128838220#!/compare/1527379200/1527552000

Sale 11:

Sold for Phosphorus Ye Oiled Baker Boy

Seller: https://backpack.tf/profiles/76561198317658037#!/compare/1522368000/1522540800

Buyer: https://backpack.tf/profiles/76561198061902266#!/compare/1522454400/1522540800

May be better to use on the Baker Boy.

Sellers:

23 keys:

https://i.imgur.com/Ckxidft.png

https://backpack.tf/item/2324671208

24 keys:

https://i.imgur.com/DEYqkpb.png

https://backpack.tf/item/2590256521

25 keys:

https://i.imgur.com/jAanQwP.png

https://backpack.tf/item/3599532884

https://backpack.tf/item/2427474318

Sales at:

22 (3x)

24 (4x)

26

https://backpack.tf/suggestion/5b16b91a44325a46c475dc24 - Seller at 23 was unsold at 26 for ~2 months, and there are several sellers for significantly cheaper than 26. Excluding 26.

Going with 22-24.