Select an Exchange
Exchange: You have to create an account at one of the many exchanges
(e.g. Kraken: Buy, Sell and Margin Trade Bitcoin (BTC) and Ethereum (ETH) , Bitstamp🙂 and there you will get a new Bitcoin wallet.
Transfer your Bitcoin to that exchange
To be able to sell now you have to transfer your Bitcoin there. After your Bitcoin has arrived in the new wallet, you can sell and transfer the Fiat amount (the money e.g.: Euro, GBP, USD) to your bank account. The advantages are that you can also use the exchanges for day trading (buying and selling several times on the same day). IMPORTANT! On exchanges the operators must have access to your Bitcoin Wallet (i.e. on your “private key”).
Now the big danger is if the exchange is hacked, because then your Bitcoin are in big danger to be stolen. This has happened several times in the past (Google “mtgox” Mt.Gox - Wikipedia) and in this case no insurance will cover the damage!
Fees: It is very difficult to determine the fees, because it depends on many different cost positions, like e.g: Entry fee, trade fee, payout fee. My experience is that the fees are around 0.35-0.45%.
Payout service providers: There are some service providers who exchange Bitcoin for Fiat and transfer the money directly to a bank account (e.g. in: EUR, USD, CNY, …). This means that you send your Bitcoin from any wallet to them and they transfer the amount minus a fee to your account (or another bank account of your choice e.g. to your landlord to pay the rent).
This is very easy to use and I have had good experiences with Bitwala: Pay Bills with Bitcoin & Load your BTC - VISA® debit card - Bitwala.
The fees are low (0.5%) and there is no risk of hacker attacks. The money was on my account after only one day.
Bitcoin Credit Cards/ Bitcoin Prepaid Credit Cards: The third option is to get a Bitcoin credit card. They are not actually credit cards (credit card = cardholder has granted you a credit).
But this is never the case with Bitcoin credit cards], but actually prepaid cards from Visa and are very useful. With Bitcoin cards you can shop online and offline and pay even where Bitcoin is not yet accepted. But please make sure to get a real prepaid card, because here only you have the “private key”.
Unfortunately, the terms are not always clearly separated from users and providers. Bitwala: Bitwala Bitcoin Debit Card - Take Your Bitcoin Anywhere offers a prepaid credit card that I have been using myself for some time.