To buy and sell Crypto you must have an account on an Exchange.
|Excerpt from Wikipedia|
Mt. Gox was a bitcoin exchange based in Shibuya, Tokyo, Japan. Launched in July 2010, by 2013 and into 2014 it was handling over 70% of all bitcoin (BTC) transactions worldwide, as the largest bitcoin intermediary and the world's leading bitcoin exchange.
In February 2014, Mt. Gox suspended trading, closed its website and exchange service, and filed for bankruptcy protection from creditors. In April 2014, the company began liquidation proceedings.
Mt. Gox announced that approximately 850,000 bitcoins belonging to customers and the company were missing and likely stolen, an amount valued at more than $450 million at the time. Although 200,000 bitcoins have since been "found", the reasons for the disappearance - theft, fraud, mismanagement, or a combination of these - were initially unclear. New evidence presented in April 2015 by Tokyo security company WizSec led them to conclude that "most or all of the missing bitcoins were stolen straight out of the Mt. Gox hot cryptocurrency wallet over time, beginning in late 2011."
The exchange will allow you to submit money from your bank or credit card, and use that to purchase crypto. You can then keep the crypto on the exchange so that you can sell it again, but exchanges have been hacked and it can be risky. See the story of Mt Gox to the right. Best practises are to transfer it to a wallet.
Keep in mind that exchanges charge fees for each transaction.
I use two exchanges, depending upon where my money is coming from.
In Canada, I use Coinsquare.com as it allows Interac Email Money Transfer and receives the money to my account within 30 minutes.
In the UK I use Binance.com because it has the lowest fees I could find. Transfers into the exchange (cash or crypto) are free. Withdrawls of Bitcoin cost 0.0005 BTC (~$14 USD) for normal withdrawls, and can go as low as 0.0000014 BTC (less than 4 cents USD). Rates depend upon the type of address you send to, as wallets support different types of addresses. Ether withdrawls vary from 0.005 ETH ($3.65) down to 0.000052 ETH (less than 4 cents). You can view all their rates here - https://www.binance.com/en/fee/depositFee