Bubbling Company Man

Sale 1: 14 keys + 14 refined; rounding to 14 keys

https://backpack.tf/profiles/76561198107891860#!/compare/1529020800/1529107200

Sale 2: 15 keys + 16 refined; rounding to 15 keys

https://backpack.tf/profiles/76561198238592900#!/compare/1528329600/1529366400

Sale 3: 15 keys pure

https://backpack.tf/profiles/76561198120469292#!/compare/1525046400/1525392000

Sale 4: ~15 keys

https://backpack.tf/profiles/76561198043220598#!/compare/1525824000/1526083200

Sales 5-6; at 25.00 USD (~13 keys) and 24.50 USD (~13) on mp.tf https://marketplace.tf/items/523;5;u34

Both sales round to 13

Sale 7: Sold for Stormy Storm Nappers + ~2 keys sweets

https://backpack.tf/profiles/76561198026198026#!/compare/1528588800/1528675200

https://backpack.tf/profiles/76561198097138683#!/compare/1528588800/1528675200

Can be used there

Sale 8: Sold for Circling Peace Sign Head Hedge

https://backpack.tf/prof6iles/76561198104116470#!/compare/1531267200/1531353600

Better used there

Sale 9: Bulk

https://backpack.tf/profiles/76561197996095002#!/compare/1530835200/1530921600

Sale 10: Bulk

https://backpack.tf/profiles/76561198125791160#!/compare/1529712000/1529798400

https://backpack.tf/profiles/76561198027338258#!/compare/1529712000/1529798400

Sale 11: Bulk

https://backpack.tf/profiles/76561198152700942#!/compare/1529452800/1529539200

Sale 12: Cash-out

https://backpack.tf/profiles/76561198075532147#!/compare/1529193600/1529280000

Sale 13: Untraceable

https://backpack.tf/profiles/76561198161149451#!/compare/1527379200/1527552000

Sale 14: Untraceable

https://backpack.tf/profiles/76561198069655849#!/compare/1528761600/1528848000

https://backpack.tf/profiles/76561198107891860#!/compare/1528761600/1528848000

Sale 14: Untraceable

https://backpack.tf/profiles/76561198043220598#!/compare/1526947200/1528243200

Sale 15: Untraceable

https://backpack.tf/profiles/76561198161149451#!/compare/1525824000/1526169600

https://backpack.tf/profiles/76561198312583107#!/compare/1526083200/1526169600

Buyers at 13; seller at 16; matured at 17. https://i.imgur.com/jVKSAxb.png

Sales at: 13, 13, 14, 15, 15, 15

Suggesting range from 14 to 15. Excuding 13 based on plenty of other sales which are not countered by buyers.