Alfred is absolutely the most game-changing app I've ever been introduced to. I only use it for finding files, searching, opening a page by direct URL, defining words, calculator, translation (via Google), launching apps, and quickly jumping to apps that are already open. It's probably saved me hundreds of hours in clicking around, etc.
I've never purchased the paid version (been using since 2011), but I support them by searching Amazon (results are via affiliate link) when I buy things.