can somebody recommend me free plugins?

That was summed up in a particularly silly post in an old thread about clipping - it wasn't my idea originally. The quick, smurf-free explanation is that one just winds up pushing each individual squisher less and getting less pumping, crackling, and the like.

Jeff
 
Did an extensive research on free plugins this year. The ones that I recommend the most are

Clipper: Gvst - Gclip
HPF/LPF: Gvst - Gband
Maximizer: Tin Brooke Tales - TLs Maximizer
Compressor/Limiter: Variety Of Sound - Density MKII (I can´t stress enough how good this plugin is)
Analyzer: Voxengo SPAN

I´m not sure if Reaper´s plugins works on other DAWs and if they´re considered free, but the ReaPlugs suite is great.