Paying taxes depends on which country you are purchasing Bitcoin in. In the United States, Bitcoin is considered a property, so you're legally obligated to report your bitcoin as a property investment, and pay capital gains taxes on it if the value appreciates.
If you're talking about an exchange tax, most exchanges take a small (usually very small) percentage of the overall value of the transaction when making an exchange.
If you're asking about general taxes, it might help to know which country you're from before you'll find the answer you're looking for.
thank you so much. I am from Norway
do all the normal people have to know about the tax system? i am 100% ignorant about this kind of things. it can be really tricky for people like me to get into legal trouble for things like this. I don't wanna get into any trouble. so i wanna pay all the taxes that I am required to
capital gain is tax for the 100usd capital plus the 50usd profits? if so, i could lose money selling at that price. its not even enough to cover the money i invested....