[KillerGardevoir]

I just had this idea and after searching the site found alot of people doing something with PVC skeletons and coroplast inbetweens(technical term i don't know it) but was wondering if anyone had a definitive way of doing this effectively because (after I buy a new car, current one has some sort of acceleration gas mileage trouble) I want to start modding my car but doing it cheaply and not bankrupt me (high school student).

Also i'd like to know if anyone knows a place that sells coroplast in northern Idaho, eastern Washington area because I know of very few places that could have it (close to none)