Sale #1:

http://backpack.tf/profiles/76561198088372680#!/compare/1478044800/1478390400

Sold at 19 keys

19 keys

Sale #2:

http://backpack.tf/profiles/76561198154516788#!/compare/1478131200/1478217600

Sold for a Stormy Storm Cosa Nostra Cap (21.5 keys) + Strange Chicago Overcoat (1 key) + Killstreak Festive Ambassador (1 key)

Overall, around 23.5 keys, but I'll round up because 19 - 23.5 is a horrible range.

24 keys

Killstreak Festive Ambassador Mini:

http://steamcommunity.com/market/listings/440/Killstreak%20Festive%20Ambassador

http://steamcommunity.com/market/listings/440/Mann%20Co.%20Supply%20Crate%20Key

Ambassador was around $1.75 at the time of the sale, and keys were $2.30. Therefore, the Killstreak Festive Ambassador was around .75 keys, and I'm rounding up to 1 key.