A basic plastic material is one of the simplest shaders to create. What you need is a Diffuse color, Fresnel Reflections (IOR in the 1.45~2.4 range, since various plastics can have different IOR’s), and a simple Bump map to break up the artificially smooth look.
Here’s the setup:
Bump is actually a mix of two differently-sized Noise maps to create a more natural look.
For shiny, glossy plastic, use a Glossiness value of 0.95~0.99. To make a matte or diffused look, just bring it down into the 0.6~07 range. In this example, we are using a greyscale map for the blurred reflections, but the map is very low contrast, so the effect is quite subtle.
