Five dollars? Seriously? Buy this. Buy this now. It's easily worth 3-4 times that price. If you like more freeform roleplaying, if you like quirky horror in the vein of Coraline or the darker parts of The Phantom Tollbooth, if as a GM you enjoy telling a story but don't like having to keep track of a bunch of different statistics , then this is definitely the game for you. Don't Rest Your Head has the honor of hosting the single most successful roleplaying campaign I've ever done.
First off, I'm a big fan of Don't Rest Your Head's system because it manages to get around the morass of technical rules that bog down other systems. Combat, skill checks and other obstacles are all resolved with the same type of roll, making the system incredibly easy to pick up, and the simplicity of the dice rules makes it easy to resolve the conflict quickly and move on with the story. At the same time, the system has a number of clever features that mechanically reinforce the game's main themes: limited personal resources, pyrrhic victory, and eventual burnout. This is not a game for power gamers; player characters WILL spend the campaign on a slow downward spiral towards oblivion, or worse. But hey, that's what makes it an effective horror game.
The only caveats and complaints I have are these: first, your group absolutely has to be dedicated to building a story together. Even one player who's more interested in throwing dice than roleplaying can throw off the dynamic. A bad GM is even worse, because the game achieves its simplicity by taking a lot of power away from the dice and giving it to the GM. Second, the game has highly unusual dice requirements; while it runs entirely on d6s, it requires that each player have a certain number of dice of distinct colors (specifically, three of one color, six of another, and six of a third). This requirement is mechanically important, so make sure you can meet it.
My favorite thing about this system, though, is its infinite potential of expansion and customization. The book does a pretty good job of laying out a solid foundation for the Mad City and its inhabitants. Officer Tock, the Tacks Man and Mother When are all antagonists that can make players wet their pants if played right. However, should you want to introduce a unique challenge or antagonist to your game, it's simple as can be: just come up with a concept and assign it a Pain rating based on how difficult you want it to be. Easy. You'll spend more time figuring out how to make your original creations work narratively than making them work mechanically, which is just as it should be.
Overall, if you're like me and you love roleplaying a good story, you're going to be enormously fond of this system and setting. I'd consider it fairly priced at $15; at $5, it's an absolute steal. Buy it.
[5 of 5 Stars!]