LocalBitcoins Popular. The time it takes to buy Bitcoin varies depending on the payment method and platform you use. Check the terms and conditions of your broker or crypto exchange for details of average processing times, and remember that the amount of activity on the Bitcoin network can also have an effect. There are hundreds of platforms to choose from, and they can be separated into three main categories: Bitcoin brokers Brokers offer the quickest and easiest way to buy Bitcoin, allowing you to pay for your digital coins using fiat currency like GBP or USD.