from what i can see it all depends on what your wanting out of it all, if you what something where you can put major amounts of detail use paper/resin... if you want cheap use foam i guess but it can be harder because of the way you have to think about the build, its like making 3d model in maya or max you got 2 visualize the object in 3d and build it from there, its hard foir me to explain... but its one of the reasons why all my bros are bad at computer modeling because i was unable to explain the mindset all the way through.... the way i'm going about it is that i'm learning how ppl here are doing it and then i'm thinking on different materals i can use to get the same effect but would be cheaper... this is where doing your reseach is key in the projects
oh an informer maybe correct but i can see how it might be hard getting any answers from ppl through pm's but still its a little waste of space for a question of this size