Buy the physical box sets (often found at very low prices at Walmart or eBay) and import them into your computer via a disc drive. This is often the most cost-effective way to get high-quality (FLAC or 320kbps MP3) files.

: His music is not available on Spotify as it does not support his preferred exclusive distribution model. Garth Brooks Partners With Amazon Music for Streaming Deal

Garth Brooks actually invented his own solution to piracy: (now integrated into Amazon).