Where can I get a mask of Barack Obama?

If you can't get it, make one yourself :p

We don't really celebrate Halloween here, so I doubt you'd get this mask in local shops, lol.

Like @moricien said, your best bet is eBay/amazon or other shops on the internet, most probably abroad.

Have you tried ebay? I've checked it, there are plenty of models available. You can check it on ebay itself.