https://steamcommunity.com/market/listings/440/Haunted%20Shoestring%20Budget

Aug 16, 0.777 keys = 41 ref

Aug 19, 0.766 keys = 40.44 ref

Aug 19, 0.781 keys = 41.22 ref

Aug 21, 0.786 keys = 41.44 ref

Aug 22, 0.816 keys = 43 ref

Aug 25, 0.974 keys = 51.33 ref

Aug 28, 0.730 keys = 38.55 ref

Aug 30, 0.646 keys = 34.11 ref

Aug 30, 0.737 keys = 38.88 ref

Aug 30, 0.684 keys = 36.11 ref

Aug 30, 0.737 keys = 38.88 ref

Aug 31, 0.740 keys = 39 ref

Sep 1, 0.826 keys = 43.55 ref

Sep 2, 0.721 keys = 38 ref

Sep 2, 0.832 keys = 43.88 ref

Sep 4, 0.927 keys = 48.88 ref

Sep 5, 0.950 keys = 50.11 ref

Sep 6, 0.947 keys = 50 ref

Sep 7, 0.946 keys = 49.88 ref (x2)

Sep 7, 0.978 keys = 51.55 ref

Sep 7, 0.838 keys = 44.22 ref

Sep 7, 0.902 keys = 47.55 ref

Sep 9, 0.968 keys = 51 ref

Sep 10, 0.968 keys = 51.11 ref

Sep 11, 0.842 keys = 44.44 ref (x2)

Sep 11, 0.838 keys = 44.22 ref

Sep 11, 0.975 keys = 51.44 ref

Sep 13, 0.747 keys = 39.44 ref

https://marketplace.tf/items/tf2/557;13

Aug 17, $1.99/1.83 = 1.08 keys

Aug 23, $1.99/1.84 = 1.08 keys

Aug 26, $1.99/1.83 = 1.08 keys

Aug 27, $1.99/1.81 = 1.09 keys

Excluding four sales on both ends for a tighter range.