Do you love big bluegill?
Their silicone mold making supplies are as reasonably priced as you'll find anywhere.
Use LEGO's to make mold forming structures. Erect a box of LEGOS, srpay in mold release and make a mold in the box. When the silicone is cured take down the LEGOS and voila! - a mold.
This may be new territory for you, so do your research first on how to do it. Model makers do this all the time.