If you want to use wood try western cedar. It is very soft and a 6 ft. fence paling will provide you a lifetime supply for about $2.50. EVA foam is everywhere, flip flops, children's toys (check for puzzles and toys made to be taken apart or put together) if you know the management or maintenance guys at a public swimming pool they can probably supply with with a lifetime supply of mismatch flip flops in one summer.
All kinds of metal tubes can be made into cutters, my favorite come from wrecked umbrellas.
Colored Sharpies are very handy for coloring bodies and rubber legs. Run a Sharpie down a twisted rubber leg gives you a candy stripe around it. Super Glue will change the color of Sharpies however. Also make friend with a teenage girl they have tons of unused finger nail polish that is good for painting bodies.
A variable chuck on your rotary tool is a neat thing, it allow you to hold tools down to needle size. I like to use a very small wood screw and thread the foam cylinder on it in my rotary tool for shaping with an emery board or sandpaper.