I would like to suggest a few items for you. Having gone to molding and casting, I have noticed that my shopping cart adds up fast with accessories but I have had good results so far. For making the mold, I have used Dragon Skin (Smooth-on.com) very effectively. It captures excellent detail from the source material. Along with this, you need the Thi Vex thickener for the last 2 layers. You would then need something to make a "mother mold". Plasti paste is what I use for this. You could also use plaster or something else. Once I have a mold, you can try Alumilite liquid plastic to create a solid "shell" of your object. Try here:
http://www.artistcraftsman.com/servl...--Super/Detail for one source. Once I have my shell, I fill it with FoamIt from Smooth-on. You can also just fill your mold with foam. Your mold should last for many, many castings (sometimes over 200!). Another way (and possibly cheaper) is to use Flex Wax to make a mold. I haven't had a chance to try this out, but am looking forward to using it this season. I can't really say what the best place is to buy these products but personally I buy direct from Smooth-On. They always get me my products very quickly. They offer solid foam (FoamIt) as well as flexible Urethane foam (FlexFoamIt) and all come in different densities and expansion rates. Good luck and keep reading!