Hardware wallets have really good security if you have over 10 bitcoins you should buy it. use linux os.
read reviews : https://www.coingecko.com/buzz/trezor-bitcoin-hardware-wallet-review

Usefully tutorial thanks will take a look at this, can you just tell me what is the real website to buy them?

They are about as safe as it get's if used properly. I did a hands on with them on the forums - https://bitcointalk.org/index.php?topic=1298917.0

But official site to buy them at is https://www.buytrezor.com/ .