5 free games this month if you have twitch prime (free with Amazon prime).

According to IsThereAnyDeal.com as of 2019/11/01 (USD) the lowest prices historically are:

Darksiders II: Deathinitive Edition - $2.99

Double Cross - $4.99

Planet Alpha - $4.99

Turmoil w/ The Heat is On - $0.99

Sword Legacy: Omen - $3.59

Which brings us to a total of: $17.55

Steam Game Pages:

Double Cross

Darksiders II: Deathinitive Edition

Planet Alpha

Sword Legacy: Omen

Turmoil w/ The Heat is On

You can use the Twitch Desktop App (Windows) to play these games but can claim on the link without installing for a later date.