A few of the most popular games on Steam are on sale for $0.99 apiece, courtesy of the new Steam Autumn Sale. And all three games in question are from Valve itself, the company behind Steam and the company that has delivered some all-time classics over the years. While Valve doesn’t make as many games as it used to, many of the games it made during yesteryear are still played to this day and continue to inspire new releases. And that’s because they are of the highest quality.

For example, Left 4 Dead remains the bar for co-op first-person shooters, which is insane because it’s 14 years old. Both it and its sequel, Left 4 Dead 2 are both $0.99 until November 29. Both usually cost $9.99, which means this is a savings of $18. Since the pair of zombies games, many have tried to replicate what they do — most recently Back 4 Blood and World War Z — but none have been able to recreate the magic these games provided a couple of generations ago.

These aren’t the only S-tier games you can get for $1 though. Both the first Portal game and its sequel are also $1. Like the pair of Left 4 Dead games, this pair ranks among the greatest games of all time. In fact, Portal 2 is one of the highest-rated games ever with a Metacritic score of 95.