Can't you find a hardware store in your vicinity? There's a "stock americain" near where I live, and they sell that for a good price...
Ofcourse getting it free like h3ro said is much better

The material itself is ideal to make robots. It's beautiful, easy to work with, sturdy,...
The only small downside is that it's pretty easily scratchable, and when it's damaged you can always see it from whatever angle you look at it.