Bitcoin offers benefits to merchants as well, as transactions that involve the digital currency are secure and irreversible. Without the risk of fraud or fraudulent chargebacks, merchants can offer their products at a discount thereby generating more sales or pocket the difference themselves. In addition, with card processors out of the picture, merchants can save on the percentage cut taken by Visa / MasterCard.
An example of a nothing at stake attack is an attacker buying lots of "old stake" from users inexpensively (inexpensive to users who no longer have stake in the currency). This can be made convenient by offering small payments to users for uploading their wallet.dat. Eventually after accumulating enough "old stake", the user can begin creating blocks and destroying as many or more coin days than the network was at that time. This block generation can be repeated until it catches up to and beats the current main-chain very cheaply.
By October 2009, the world’s first Bitcoin exchange was established. At the time, $1 was the equivalent of 1,309 Bitcoin. Considering how expensive Bitcoin is today, that was a real steal. Bitcoin traded at a fraction of a penny for quite some time. Things started changing in 2010; as the distribution of Bitcoin increased, the digital currency became inherently more valuable.