Ok, so after a few more hours of watching youtube videos and reading about hardware wallets and exchanges, I now understand that MyEtherWallet will open the possibility to be able to buy a couple of hundred different alt coins as well as the 20 most popular coins on the Ledger Nano S (native support on the device).
My conclusion is thus so far that a Ledger Nano S with MyEtherWallet and Coinbase are the three things I need to buy, store and sell crypto coins. If I want more than these 220 coins (there are what.. 11.000 of them?) I need to use different online or software wallets in addition to the hardware wallet.
Am I onto something here?
MyEtherWallet supports Ethereum and any ERC-20 token (
https://myetherwallet.github.io/knowledge-base/faq/sending-bitcoin-btc-ltc-xmr-to-myetherwallet.html)
Just using Ledger Nano S/MyEtherWallet and Coinbase will not allow you to buy anything except BTC, LTC, and ETH (
https://myetherwallet.github.io/knowledge-base/getting-started/whats-the-difference-between-an-exchange-and-myetherwallet.html)
In order to buy most other currencies, you will have to use another exchange such as Bitfinex, Bittrex, Binance, Kucoin, etc. Take a look at
https://coinmarketcap.com/ and search for the coin you want. It will list the markets you can buy/selel from