The safest way to store your crypto would be in a cold wallet. Hardware wallet and desktop wallet that Zenith just suggested are great way to keep your coin secure but always remember to keep your private key / hardware wallet secured as well. One downside of using a hardware or paper wallet is that once you physically lose them, you lose your funds for good. There is no other ways to retrieve them. Therefore if you chose to keep your fund in a hardware wallet, the safety of your funds is entirely dependent on you. We have written an article on the categorisation of different bitcoin wallet. Have a look. You might find it useful.
+1 on ledger nano s. It will be a worthwhile investment. Just remember not to store your crypto on an exchange wallet if you are not planning to trade it actively. You lose your fund forever if there happened to be a hack. It happened to me once and it was a lesson well learned.
I suppose you cant go wrong with hardware wallet. I personally use ledger nano s to store my coins and the experience has been great so far. If you are looking for free yet secure way to store your coin, maybe you can have a look at Myetherwallet or metamask.