I think if we use bitcoin then we don't have to pay the tax except we need to pay the transaction fee. but if we are going to exchange our bitcoin into fiat, then I think there will be a fee that we should pay. and after the money is arriving into our account, then we should pay the tax for monthly. but I don't think that tax on bitcoin is applied right now because in the country which accepting bitcoin, the people do not pay the tax at all.