There are some ways to earn bitcoin, mining, faucet and investment.
Disclaimer & Free Advice for your all investments:
Always do your own research and only invest money you can afford to loose. These are high risk investment platforms. I personally did invest in these but everyone should make their own decisions. Use this as for information purposes only.
Here the list:
Future-bank > min depo 0.001 btc
Bitconnect > min depo $100 / convert to btc
Bit-earning > min depo $10/ convert to btc
Homeblockcoin > waiting progress
Hexabot > min depo 0.005 btc
Dekado > min depo $100
Bitcoinbanq > min depo 0.002 btc