And there it shows..

Sales

Sale 1: Sold for 20 keys

https://backpack.tf/profiles/76561198061489334#!/compare/1600473600/1600560000

https://backpack.tf/profiles/76561198135406906#!/compare/1600387200/1600560000

Sale 2: Untrace

https://backpack.tf/profiles/76561198139677649#!/compare/1589500800/1593907200

https://backpack.tf/profiles/76561198191572695#!/compare/1558224000/1597795200

Sale 3: Sold for 17 keys

https://backpack.tf/profiles/76561198418482596#!/compare/1596931200/1597017600

https://backpack.tf/profiles/76561198294542813#!/compare/1572912000/1597190400

Sale 4: 20 refined of hats were traced..

https://backpack.tf/profiles/76561198299330841#!/compare/1593648000/1596067200

https://backpack.tf/profiles/76561198418482596#!/compare/1594684800/1595721600

Sale 5: Traced 9 keys

https://backpack.tf/profiles/76561198429062799#!/compare/1600560000/1600646400

https://backpack.tf/profiles/76561198102185053#!/compare/1600387200/1600646400

Buyout was 20, was likely 20.

https://bot.tf/stats/listings/4WXDJL70

Sale 6: Untrace

https://backpack.tf/profiles/76561198420335027#!/compare/1600300800/1600560000

https://backpack.tf/profiles/76561198429062799#!/compare/1600473600/1600560000

Sale 7: Untrace

https://backpack.tf/profiles/76561198182509078#!/compare/1560556800/1600560000

https://backpack.tf/profiles/76561198420335027#!/compare/1600300800/1600560000

Sale 8: Traced a Haunted Shoestring Budget..

https://backpack.tf/profiles/76561198850178158#!/compare/1595721600/1595980800

https://backpack.tf/profiles/76561198437262525#!/compare/1589760000/1598659200

Buyout was 14 keys + 40 ref, would round to 15 keys~

https://bot.tf/stats/listings/Y807V55D

Sale 9: Sold for 13 keys + 12.22 refined

https://backpack.tf/profiles/76561198275790159#!/compare/1593388800/1593475200

https://backpack.tf/profiles/76561198850178158#!/compare/1593388800/1593475200

13 keys~

Sale 10: Traced about 38 refined of items

https://backpack.tf/profiles/76561198155249592#!/compare/1593216000/1593302400

https://backpack.tf/profiles/76561198275790159#!/compare/1593043200/1593388800

Sale 11: Sold for 13 keys + 11 refined

https://backpack.tf/profiles/76561198305494036#!/compare/1593043200/1593129600

https://backpack.tf/profiles/76561198155249592#!/compare/1593043200/1593216000

13 keys~

Doesn't appear to be a sale..

https://backpack.tf/item/2212498178

Marketplace

https://marketplace.tf/items/tf2/817;5;u57

June

$29 on June 24 (29/2 = 14.5 rounds to 15~)

https://manic.tf/keyprice/?at=2020-06-24

Listings during the time: https://bot.tf/stats/listings/4R0RXX15

24 on June 26 (24/2.03 = 12~)

https://manic.tf/keyprice/?at=2020-06-26

Listings during the time: https://bot.tf/stats/listings/4ZPD8V6Q

30 on June 28 (30/2.05 = 15~)

https://manic.tf/keyprice/?at=2020-06-28

Listings during the time: https://bot.tf/stats/listings/MNR0OWRQ

July

$9 on July 24 (9/1.94 = 5~)

https://manic.tf/keyprice/?at=2020-07-24

Listings during the time: https://bot.tf/stats/listings/M19VLQG7

30 on July 30 (30/1.92 = 16~)

https://manic.tf/keyprice/?at=2020-07-30

Listings during the time: https://bot.tf/stats/listings/MNR6ELN3

August

$30 on August 1 (30/1.91 = 16~)

https://manic.tf/keyprice/?at=2020-08-01

Listings during the time: https://bot.tf/stats/listings/4663N33L

Classifieds

https://gyazo.com/1ddb63d84dd19a7dce199105b486ed32

Summary

Sales at 13, 13, possibly 15, 17, 20, and possibly 20.

Marketplace sales at 5, 12, 15, 15, 16, and 16.

Conclusion

Buyers are up to 15.63 now. Excluding 5, 12, and 13.

Although 15 is low, that makes 3 sales at 15 which makes it common enough to include here. Multiple sales at lower to support including 15 as my low end.

Going with 15-20 here.