The process involves predicting numbers on a block until the program accepts the code and completes the transaction by assigning the BTC to the correct guess. Enter the amount you want to buy, and click «Buy Bitcoin Instantly». Ease of Use. Also one of the fastest! Should I leave my bitcoins on the exchange after I buy? The process is very hard but rewarding as the correct guess earns Buying bitcoins is hard and that’s why I built this site.