You can earn money online without spending money through various methods like writing websites, online survey sites, and affiliate marketing. Writing websites allow users to write about their interests and earn money based on votes. Online survey sites pay users for their opinions and feedback. As an affiliate, you can earn commissions by promoting other businesses and driving sales through your links. While these options require no upfront costs, it may take time to earn substantial returns, which are never guaranteed. Overall, they provide good opportunities to supplement existing income without large investments.