There are many things that you can do to earn cryptocurrency, but none of them are particularly easy. Some are downright not even profitable, and others are a waste of time.
Here are some activities that you can do for fun as a hobby in your spare time if you would like to experiment with earning some bitcoin, alt coins, and crypto for yourself.
1. Mining / CPU Mining / Cloud Mining
2. Staking Your Coins / Masternodes / Proof of Stake
3. Get friends to sign up with Referral Codes
4. Faucets (waste of time)
You can buy Bitcoin, Ethereum, Litecoin, and Bitcoin Cash here: https://www.coinbase.com/join/59b058e183ab5a00b66f67a0
You can sign up for Minergate here: https://minergate.com/a/a9be89fad3662eec68ede122