1.  Online : Participating in online surveys is an easy way to earn extra cash. Companies are always looking for consumer opinions, and will pay for your time and feedback.
2. Freelancing: Freelancing is a great way to earn extra cash by using your skills. Websites like Upwork and Fiverr allow you to offer your services to clients all over the world.
3. Online Tutoring: If you're an expert in a particular subject, you can earn extra cash by tutoring students online. Websites like TutorMe and Chegg allow you to connect with students who need help with their studies.
4. Content Creation: Creating content for websites and social media platforms can be a great way to earn extra cash. You can create videos, write articles, or design graphics for websites and blogs.
5. Online Trading: Online trading platforms like E-Trade and TD Ameritrade allow you to buy and sell stocks, bonds, and other securities. If you have a knack for picking winning investments, you can earn extra cash through online trading.
6. Online Selling: Websites like Etsy, Amazon, and eBay allow you to sell your own products online. Whether you make your own jewelry, crafts, or other items, you can earn extra cash by selling them online.
7. Online Gambling: Online gambling websites offer a wide range of games, including poker, blackjack, and slots. If you're good at gambling, you can earn extra cash by playing at these sites.
8. Online Affiliate Marketing: Affiliate marketing is a way to earn extra cash by promoting other people's products. When someone clicks on your affiliate link and makes a purchase, you earn a commission.
9. Online Advertising: If you have a website or blog, you can earn extra cash by displaying ads on your site. Websites like Google AdSense allow you to display ads on your site, and you earn money every time someone clicks on an ad.
10. Online Virtual Assistant: As a virtual assistant, you can help people with a wide range of tasks, including scheduling appointments, managing social media accounts, and responding to emails.
11. Online Data Entry: Data entry is a great way to earn extra cash if you have good typing skills. You can find data entry jobs on websites like Upwork and Fiverr.
12. Online Transcription: If you have good listening skills and can type quickly, you can earn extra cash by transcribing audio files. Websites like Rev and TranscribeMe allow you to transcribe audio files for clients all over the world.
13. Online Proofreading: If you have a keen eye for detail, you can earn extra cash by proofreading documents. Websites like Grammarly and Gramlee allow you to proofread documents for clients all over the world.
14. Online Consulting: If you have experience in a particular field, you can earn extra cash by consulting with others. You can offer your expertise on websites like Clarity.fm or LinkedIn.
15. Online Coaching: If you have experience in a particular field, you can earn extra cash by coaching others. You can offer your coaching services on websites like Coach.me or Clarity.fm.

In conclusion, there are many legitimate ways to earn extra cash online. Whether you have a particular skill or just a bit of spare time, there is an online opportunity that can help you to earn extra cash. It's important to be careful when considering an online opportunity, as there are many scams out there. It's always best to research any opportunity before getting involved, and to never invest more than you