Sale 1:

https://backpack.tf/profiles/76561198125791160#!/compare/1547164800/1547251200

https://backpack.tf/profiles/76561198845878276#!/compare/1546387200/1547251200

Sold for 17 keys

https://bot.tf/stats/listings/4ZJJJ8DM

B/O of 17 keys

Sale 2:

https://backpack.tf/profiles/76561198150497917#!/compare/1549843200/1549929600

https://backpack.tf/profiles/76561198311902268#!/compare/1549756800/1549843200

Sold for ~14 keys in items

B/O of 24 keys

Sale 3:

https://backpack.tf/profiles/76561198311902268#!/compare/1549843200/1549929600

https://backpack.tf/profiles/76561197968968337#!/compare/1549843200/1549929600

Sold for 13 keys (keys used to buy Tailor)

https://bot.tf/stats/listings/46XRQL2Y

B/O of 15 keys

Sale 4:

https://backpack.tf/profiles/76561197968968337#!/compare/1550275200/1550361600

https://backpack.tf/profiles/76561198808612658#!/compare/1550275200/1550361600

Used there (sold for Neutron Toy Soldier)

Sale 5:

https://backpack.tf/profiles/76561198808612658#!/compare/1551571200/1552003200

https://backpack.tf/profiles/76561198152605492#!/compare/1551916800/1552003200

Sold for P Fetti Nickel(13) + ~2 keys in sweets

Total is 15 keys

Sale 6:

https://backpack.tf/profiles/76561198152605492#!/compare/1552003200/1552089600

https://backpack.tf/profiles/76561198892101673#!/compare/1552003200/1552089600

Sold with ~ 1 key in sweets for CPS Whoopee

Whoopee Mini:

https://backpack.tf/suggestion/5c8f50c86780725b5b21b49c

Suggestion for 17.5 keys

Total is 16.5 keys

B/O of 16 keys

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

Sale 7:

https://backpack.tf/profiles/76561198892101673#!/compare/1552089600/1552176000

https://backpack.tf/profiles/76561198358296372#!/compare/1552089600/1552176000

QS

Sale 8:

https://backpack.tf/profiles/76561198808612658#!/compare/1550361600/1550448000

https://backpack.tf/profiles/76561198038307962#!/compare/1550361600/1550448000

Sold for G Fetti Pampered + ~2 keys in sweets

Use there

Total sales @:

13, 14, 15, 16, 17 keys

Seller for 16, listed for a week:

https://bot.tf/stats/listings/4JZ7LQXY

Buyers up to 12 keys,

Considering 13 was after the 14 sale, and was done real quick,

Taking 14 - 16 keys