https://marketplace.tf/items/tf2/30807;5;u110

May 14 - $26.69 / $1.90 = 14.05 keys

June 5 - $23.5 / $1.96 = 11.99 keys

June 6 - $24 / $1.99 = 12.06 keys

June 9 - $23.83 / $1.99 = 11.97 keys

June 20 - $25.99 / $1.98 = 13.13 keys

June 24 - $27.99 / $2.00 = 13.99 keys

June 29 - $17.01 / $2.01 = 8.46 keys

July 6 - $30 / $1.99 = 15.08 keys

July 9 - $30 / $1.99 = 15.08 keys

July 24 - $24.95 / $1.94 = 12.86 keys

https://backpack.tf/item/7536394704

https://backpack.tf/item/5211681477

https://backpack.tf/item/5364863496

https://backpack.tf/item/5502199559

//

https://backpack.tf/profiles/76561198095022965#!/compare/1588809600/1588982400

https://backpack.tf/profiles/76561198049556321#!/compare/1588896000/1588982400

Bulk

//

https://backpack.tf/profiles/76561198049556321#!/compare/1588982400/1589068800

https://backpack.tf/profiles/76561198337734785#!/compare/1588982400/1589068800

Untraceable, something with Purple Confetti Law

//

https://backpack.tf/profiles/76561198337734785#!/compare/1589068800/1589155200

https://backpack.tf/profiles/76561198110720167#!/compare/1589068800/1589241600

28 item stack, which is 10 keys and 18 refined

//

https://backpack.tf/profiles/76561198110720167#!/compare/1589241600/1589760000

https://backpack.tf/profiles/76561198093170043#!/compare/1578873600/1589328000

Untraceable

//

https://backpack.tf/profiles/76561198093170043#!/compare/1589414400/1589500800

https://backpack.tf/profiles/76561198845140080#!/compare/1589414400/1591142400

Untraceable

//

https://backpack.tf/profiles/76561198845140080#!/compare/1589414400/1591142400

https://backpack.tf/profiles/76561198260686830#!/compare/1589328000/1589414400

Untraceable

//

https://backpack.tf/profiles/76561198260686830#!/compare/1589414400/1589500800

https://backpack.tf/profiles/76561198169925494#!/compare/1585872000/1592697600

Untraceable

//

https://backpack.tf/profiles/76561198041128669#!/compare/1592265600/1592352000

https://backpack.tf/profiles/76561198850266056#!/compare/1592179200/1592352000

https://gyazo.com/492a94129bc6cf864d08efe2cb051cc0

1 @ 9 keys, 23.66 ref 7/16/2020, 4:58:00 AM

bot.tf buy

//

https://backpack.tf/profiles/76561198850266056#!/compare/1595980800/1596067200

https://backpack.tf/profiles/76561198036385359#!/compare/1594512000/1596067200

Untraceable

//

https://backpack.tf/profiles/76561198255079651#!/compare/1593302400/1593388800

https://backpack.tf/profiles/76561198357873392#!/compare/1593648000/1593993600

Untraceable

//

https://backpack.tf/profiles/76561198357873392#!/compare/1594598400/1596153600

https://backpack.tf/profiles/76561198335791307#!/compare/1594857600/1594944000

bot.tf buy

1 @ 9 keys, 23.66 ref 7/16/2020, 4:58:00 AM

//

https://backpack.tf/profiles/76561198335791307#!/compare/1595980800/1596067200

https://backpack.tf/profiles/76561198877538762#!/compare/1594425600/1596153600

https://bot.tf/stats/item?def=30807&q=5&ef=Starstorm%20Slumber&craft=1&aus=0&ks=0&source=browser_script

https://gyazo.com/492a94129bc6cf864d08efe2cb051cc0

12 keys, bot.tf sale

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Sales:

8.5

9.5

9.5

10

12

12

12

12

13

13

14

14

15

15

8.5 is low marketplace sale

9.5s are both bot.tf buys

and 10 just looks low in comparison

Going with 12-15 keys