Why People Buy Cryptocurrency. When computers successfully add a block to the blockchain, they are rewarded with cryptocurrency. The Cash App allows users to buy and sell bitcoin without processing fees. Bitcoin can be sold, traded for a product, or bought into like a stock which this article will teach you how to do. That means investing in bitcoin now should be a sure-fire bet to pay off four years down the road, right? Keep in mind you can also sell your own products for Bitcoin, making these marketplaces an easy way to build up your Bitcoin investment.