Hi all, please excuse the noob question, but I have never purchased an app on the Mac App Store and am looking to buy Mountain Lion when it comes out. The price is 19.99, so would I buy a $20.00 iTunes card? Or will there be taxes included on top of that 19.99, thus needing more than a $20.00 card? By the way, I live in Canada, if that matters RE: tax. Am just not sure if 19.99 is the flat rate. Thanks for the help in advance!