Here's how to make $400 through online using different approaches without investment.

Teach English Online

You can make up to $22 per hour teaching English to kids via video chat at VIPKid. You get to choose your own hours as well.

At GoGoKid, you have a forum similar to that. To work from home teaching English online, you get paid up to $25 per hour.

You also have a website like SayABC, which will pay you up to $19 for 40 minutes. The hours are also very flexible here.

You should be able to get enough work to make $100 a day or more, with both of these places combined.

By offering a lot of templates and lesson plans, these sites also make it simple for you.

Affiliate Marketing
You can make money through affiliate using a mix of free websites from either WordPress.com or Weebly, videos from YouTube, social media, and other forms.
You would need to either have a free website with traffic to help you get accepted for programmes such as Amazon Associates and Etsy to do this without investment, or just sign up for a website like Clickbank that doesn't require one.
Either way, you probably won't be able to collect emails to keep this process free of cost (which is how top affiliates make their money). This matters because it means that the visitor conversion rate to consumers would be much smaller than those who use email over time to sell to subscribers. Looking for a $400 loan? Please visit 400loan.com

Freelance Services

What's great about freelance services is that you can only make money from the talents you already have and don't have to build a website.

Sites like UpWork, Fiverr, and PeoplePerHour have more freelance jobs available than you could imagine and you can only build a profile for free to get started.

Many top freelancers receive $100 per hour or more once the prestige of their profile has been established.

Selling goods for Online Info

The selling of information products is another way to make money online without investment. EBooks, courses, etc. can include these.
Since it will almost certainly cost money, the trick is not to sell them on your own website.

Sell Art and Merchandise Digital

Last but not least, without investing a lot of money at all, you can sell digital art and merchandise online (like t-shirts and coffee mugs).

Towards digital art

Opening an Etsy store and selling art that is available through direct digital download is one thing you can do. This means they download it when people pay for your design, and can print it off themselves, however they please.

You don't have to deal with packaging, shipping, ordering, or any of the expensive problems that come with selling traditional art with this technique.