Barricade is another very nice plugin created by Jeroen Breebaart. It’s free brick wall limiter unit, which means that it has very high ratio and a very fast attack time. Ideally, this ensures that an audio signal never exceeds the amplitude of the threshold. Ratios of 20:1 and more are considered to be “brick wall”.
Barricade has separate controls for gain adjustment, limiter release time, and variable softclipping for extreme ‘overs’. Overall, it’s a simple limiter that does it’s job very good. If you need something more advanced but still free / cheap then you might consider buying commercial version of Barricade called Barricade Pro (cost: 10 EUR)
Download: Jeroen Breebaart Barricade