PTC, Faucets with a lot of referrals, Freelance is a good option too. I don't recommend HYIPs.
I am sure that the OP was not planning to earn 0.1 in his lifetime if he is going to try faucets 
Signature campaigns, although it isn't much of a secret 😀
Signature campaigns is not a way to earn 0.1 in a weeks time.if he is planning to earn in 20 weeks times then signature campaign can do the trick if you can spend some time online .To earn money you have to invest some money and try trading or gambling if you are that eager to earn.