Steam is having a sale this weekend for Halloween with a focus on scary games. All of the Resident Evil games available on Steam are discounted as well as a few other popular games like Dying Light for 29.99 (which also has their DLC half off), the Bioshock Triple Pack for 10.49, or the entire Hitman Collection for 7.99. I also think the increasingly popular open world game Ark: Survivor Evolved is the lowest it has ever been at $20.09. There are also a number of cool indie games discounted, I will highlight one called Kholat which seems a very fitting choice for this weekend. Check out this trailer narrated by Sean Bean.
Be sure to check your wishlists to see if your desired games are included and the prices are good until 10am PST on Nov. 2nd.
If you are into Steam trading cards there are a ton of games under 50 cents you can score and if you sold the cards might even make Steam credit money.