Gregory's Server@yngmar
Quality can be defined as a product (or service) that meets a particular need.
Montblanc pens are made from expensive materials, and will likely last a lifetime. However, I'd argue that Bic pens are quality in a different way. Bic pens perform the function of writing, and are cheap enough that losing one isn't the end of the world.
The difficult bit is knowing whether the brand you are buying meets your definition of quality.