Earning money online without any investment can be challenging, but there are legitimate ways to do so. 

Freelancing: Offer your skills and services on freelance platforms such as Upwork, Fiverr, or Freelancer. If you have skills in writing, graphic design, programming, marketing, or other areas, you can find clients and get paid for your work. 

Online Surveys and Reviews: Participate in online surveys and review products on websites that pay for such feedback. Be cautious and choose reputable platforms to avoid scams. 

Content Creation: Start a blog, YouTube channel, or a podcast. Once you build an audience, you can monetize through advertising, sponsorships, or affiliate marketing. 

Affiliate Marketing: Promote products or services and earn a commission for each sale made through your unique affiliate link. Many companies offer affiliate programs. 

Virtual Assistance: Offer virtual assistance services to businesses or entrepreneurs who need help with tasks like email management, social media, customer support, etc. 

Online Tutoring: If you're knowledgeable in a particular subject, you can offer tutoring services on platforms like Chegg Tutors, Tutor.com, or even independently. 

Sell Photos: If you're good at photography, you can sell your photos on stock photo websites like Shutterstock, Adobe Stock, or Alamy. 

Online Courses: Create and sell online courses on platforms like Udemy or Teachable. Share your expertise on a specific topic. 

Transcription Services: Transcribe audio files into text for clients. There are various transcription platforms where you can find work.