The simple answer is no - in all countries that I know of. However, you do need to pay transaction fees for miners.
The simple and complex answer is absolutely yes. There may be a few places like Dubai where you may not have to pay taxes. But almost every country in the world has a tax that covers bitcoin. I don't know where people come up with this notion that bitcoin is not covered by tax law. Here in the U.S. all your money is taxable. If you found a dollar on the sidewalk you would owe tax on it. It's that simple, a gain in money triggers a taxable event. sure if i found a random dollar on the street is taxable, actually this is a bit stupid because in some country of europe they don't tax you for a small sum like that, like they don't tax the homeless people that receive 1 dollar a day by begging
but let's assume that they are taxing even few cent, this is not equal to them knowing that i have found that cent which is simply impossible, thus i'm not obligated to declare anything if for them is impossble to find out
why would a government accept bitcoin as a payment option if a few people are willing to pay their taxes .Let me tell you one thing,not only are they worried about the illegal activities they are worried about the cash flow which would hurt the economy. 
