Lowertone has released a free Mac filtering app, Freeq. Freeq is spectral filtering app, designed for easy and fast frequency manipulations. You can cut and manipulate single frequencies, transforming sounds however you like.
NSFW: Think you need new gear? Think again! Analogger has a recipe for creative sound design in hard times, and it involves pitting a 70’s Hamilton Beach blender against an Access Virus. If you’ve got more ideas for crazy low-budget sound design, leave a comment!