The incredibly low-cost days of mining bitcoin, which only lasted a couple years, were days where one bitcoin was so cheap that it financially made sense to mine them at a very low cost instead of buying them. For context, the first exchange rate given to bitcoin was in October 2009, 10 months after the first block was mined. The rate, established by the now-defunct New Liberty Standard exchange, gave the value of a bitcoin at US $1=1309.03 BTC. It was calculated using an equation that includes the cost of electricity to run a computer that generated bitcoins. This was the period of time where bitcoins, which were looked at as little more than a newly created internet novelty, could be mined in large quantities using an average computer.
Whenever referring to the price of Bitcoin as it relates to fiat currency, the price being discussed is almost certainly an aggregate average of the price across various exchanges’ order books. Because bids and asks are instructions executed at a certain price, a large market buy would fill through several orders at incremental price levels and subsequently move the price of bitcoin up or down.
The Bitcoin world, in my opinion offers such arbitrage opportunities. But they are not as simple to execute as it might seem at first sight. Price differences between exchanges often come for certain reasons. The speed of fiat money transfers and access restrictions are just the most striking ones. You have to find out the concrete opportunities yourself. One place to start is this thread on Bitcoin StackExchange. Also, not every opportunity is available to everyone. Go and have a look at the price differences between exchanges and check out if you can find opportunities.
Even recent entrants like Uber and AirBnB are threatened by blockchain technology. All you need to do is encode the transactional information for a car ride or an overnight stay, and again you have a perfectly safe way that disrupts the business model of the companies which have just begun to challenge the traditional economy. We are not just cutting out the fee-processing middle man, we are also eliminating the need for the match-making platform.

According to The New York Times, libertarians and anarchists were attracted to the idea. Early bitcoin supporter Roger Ver said: "At first, almost everyone who got involved did so for philosophical reasons. We saw bitcoin as a great idea, as a way to separate money from the state."[120] The Economist describes bitcoin as "a techno-anarchist project to create an online version of cash, a way for people to transact without the possibility of interference from malicious governments or banks".[123]

There are many Blockchain projects which aim to do this. Bear in mind, however, that there is often not enough storage within Blockchains themselves, but there are decentralized cloud storage solutions available, such as Storj, Sia, Ethereum Swarm and so on. From the user’s perspective they work just like any other cloud storage. The difference is that the content is hosted on various anonymous users’ computers, instead of data centers.
Voting with blockchain carries the potential to eliminate election fraud and boost voter turnout, as was tested in the November 2018 midterm elections in West Virginia. Each vote would be stored as a block on the blockchain, making them nearly impossible to tamper with. The blockchain protocol would also maintain transparency in the electoral process, reducing the personnel needed to conduct an election, and provide officials with instant results.
Bitcoin faucets have been around since at least 2011. It is believed that Gavin Andresen owned the first one. They come and go and often enough are just advertising scams – the owners want users on their site so they tempt them with free Bitcoin that never actually materializes because before the users have made enough to “cash out” the site has disappeared.

Though transaction fees are optional, miners can choose which transactions to process and prioritize those that pay higher fees.[69] Miners may choose transactions based on the fee paid relative to their storage size, not the absolute amount of money paid as a fee. These fees are generally measured in satoshis per byte (sat/b). The size of transactions is dependent on the number of inputs used to create the transaction, and the number of outputs.[3]:ch. 8

Legal Gray Area. Major governments have largely remained on the sidelines, and this has created both a sense of potential and apprehension for Bitcoin proponents and critics respectively. Bitcoin isn’t backed by a regulatory agency and a government would technically be ceding power by supporting a decentralized currency. This has been largely officially unaddressed. Bitcoin’s price, however, tends to be very sensitive to any news concerning the US government’s opinion of cryptocurrencies. For example, when the SEC denied the approval of bitcoin-based exchange-traded-products—essentially bitcoin-backed assets on the stock market—in 2017, Bitcoin’s price dropped 18%. Yet while the price and adoption of Bitcoin would be affected by government action, governments are unable to criminalize Bitcoin. In fact, governments such as the United States and China have invested in it at some capacity.
Then cryptocurrencies came along and turned this traditional source of wealth creation on its head. When 2017 began, the aggregate value of all digital currencies combined equaled just $17.7 billion. However, as recently as this past weekend, the combined market cap of the nearly 1,400 investable cryptocurrencies was almost $836 billion. That better than 4,500% increase in value is something that the stock market would take multiple decades to accomplish.
Perhaps one of the best real-world examples of blockchain in action is the partnership between Ripple (CCY: XRP-USD) and banking giants American Express (NYSE:AXP) and Banco Santander (NYSE:SAN). It was announced in mid-November that American Express users would be able to send non-card payments to U.K. Santander accounts over AmEx's FX International Payment network and have those transactions processed over Ripple's blockchain. The allure of this partnership is Ripple's instantly settling cross-border payments, as well as the expectation of small transaction fees. 
Block-chain technology is broader than finance. It can be applied to any multi-step transaction where traceability and visibility is required. Supply chain is a notable use case where Blockchain can be leveraged to manage and sign contracts and audit product provenance. It could also be leveraged for votation platforms, titles and deed management - amongst myriad other uses. As the digital and physical worlds converge, the practical applications of Blockchain will only grow.

Transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. Bitcoin was invented by an unknown person or group of people using the name Satoshi Nakamoto[9] and released as open-source software in 2009.[10] Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies,[11] products, and services. Research produced by the University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.[12]