I called out the price fluctuations breathlessly to my wife, who gently encouraged me not to be an idiot, before returning to her magazine. Find a Bitcoin Exchange. The ATMs let you exchange bitcoin for cash, or vice versa by scanning a QR code from the digital wallet application on your phone. Throughout its history, Bitcoin has generally increased in value at a very fast pace, followed by a slow, steady downfall until it stabilizes. Transactions are added to «blocks» or the links of code that make up the chain, and each transaction must be recorded on a block.