Toy camera implies cheaply made and usually, though not always, comes with a certain aesthetic. I prefer lo-fi appearance in a more reliable body, so tend to favour older folding cameras for the same role. The name toy derives from the fact many were originally aimed at children, and have play value but not high expectancy of a long life, which can be a problem if you're relying on one.

Polaroid probably gets lumped in with toy because the resulting print is small and 'toy-like'.