Rui CarmoCrystal is a completely free software synth (for Windows and Mac) that works as a VST plugin (or Audio Unit) inside other programs (it is rumored to work inside GarageBand, for one):
Crystal is a completely free software synth (for Windows and Mac) that works as a VST plugin (or Audio Unit) inside other programs (it is rumored to work inside GarageBand, for one):