So I received an email from the good folks at MacUpdate, saying that they have listed Sound Booster. They also asked if there is a demo version available that is independent of the Mac App Store.
This got me thinking, because when the idea of Sound Booster was conceived, I wanted to make a free version with basic features, then add In App Purchases for the more advanced features that people might want. However, Apple did not allow this on their App Store due to a conflict with their policies, so I scrapped that plan and made the entire app a one-time-purchase of $5.99.
So, after this kind reminder from MacUpdate, I got to work and produced a Lite version of Sound Booster that is independent of the Mac App Store. It has system-wide volume boosting for all running apps, boosting volume for mp3 files on all devices, etc, all for FREE. For more features like a system-wide equalizer, individual volume adjustments, and other advanced features, one could easily upgrade to the full App Store version.
So there you have it. Download Sound Booster Lite now and enjoy system-wide volume boosting for free!