If you want your photos to look professional, you have to use professional techniques.
Frequently, DIY tools simply cannot provide professional looking results.
Professional techniques, if you understand lighting, angles of incidence, colour/specular reflectance etc, it matters little how you achieve it, as GS states poly or foam boards are widely used here.
I also know another tog gets great results using twenty dollar halogen lighting from a builders merchants rather than pay out for less powerful but vastly more expensive continuous lights from photographic suppliers.
Some of the garbage on here with regards to lighting really gets my back up, set ups of studio lighting in the park, all the off camera crap its a wonder any of you lot over there ever take a photograph. The old saying "if the cap fits", has its place in photography as well as elsewhere, foamboard is as good as it gets. H