While the official Waves SSL G-Master Buss Compressor is a paid product, you can access it or high-quality alternatives through the following methods: SSL Native Bus Compressor 2 - Solid State Logic
Once you've downloaded your free alternative, use these "Magic Settings" to get that G-Master sound: 4:1 (for punch) or 2:1 (for subtle glue). Ssl G-master Buss Compressor Free - Download
Solid State Logic offers a 14-day, fully functional trial of their , which includes the Channel Strip 2 and the G-Master Buss Compressor 2 . While the official Waves SSL G-Master Buss Compressor