No, it doesn't include everything under 5 bucks. Heck, it doesn't even include everything from the same publisher that is under 5 bucks, which leads me to believe there is an issue with the algorithm. There are over 2,300 OSR releases that are under 5 bucks. Below, I'm highlighting a few with minimal if any commentary.
Starfaring Exploration for Delving Deeper and OSR -
Wyrms & Warlocks: Medusa's Hunger
VS1 - The Caves of Ortok - Labyrinth Lord Edition -