Whether you are a creator or just someone who likes listening to soundtrack-like music, the Big Music Bundle 2 (affiliate link) from Humble Bundle is a great option for you. At the price of at least $25, you can score 24 packs of music.
This includes action rock, emotional strings, retro gaming, and many more types of music for you to use. All of this is royalty free which allows you to use it in whatever creative projects you work on. In addition, each purchase will support JDRF, Cancer Research UK, and a charity of your choice.
What are you going to be using these tracks for?