Welcome to Buy Bitcoin Worldwide! In most countries you will need to pay some kind of tax if you buy bitcoins, sell them, and make a gain. Compare Investment Accounts. They vary for credit card and bank transfer. As with any market, nothing is for sure. There can never be more than 21 million — and there are about As the most popular form of cryptocurrency and the blockchain technology that powers it Bitcoin is now widely accepted around the world and has a growing number of applications.