Great list here Yaro, thank you so much for sharing. I think combining some of these you can get a real steady income going. I agree with the fact that $250 is a great amount for reviewing other products, but like you said that can become something rather tedious and will not allow you to be truly free. As well you will not be writing what your passionate about.
Creating space for banner ads on your website is another way to generate a revenue from adverts. However, for this type of advertising, you will need to contact businesses directly and ask them if they would like to advertise on your website. The upside is that you can charge a set amount, or even a recurring monthly fee, to business to promote their services on your site. Using a WordPress plugin like AdSanity is an effective way to manage this type of advertising.
Some subjects are much better paid than others, so although you may love the idea of writing about travel (badly paid) a better bet would be a niche like finance (much higher rates of pay). Check out the Pro Blogger job board for high paid freelance writing jobs – other places to look might be Textbroker or you can look at the “gigs” section on Craigslist.
Proz.com is a site where you can get paid to translate all kinds of documents, including files and even conversations. The site provides you with an opportunity to list your services as a translator. They offer opportunities in Spanish, German, Italian, Chinese, Arabic, Japanese and other languages, and specialize in legal, medical, technical and other fields.
Using a food delivery service can’t necessarily earn you money, but it can help you save you money if you constantly find yourself throwing out half the food you buy. Food delivery services send a box of food every week with new, sometimes unique vegetables, meat, fruit, and so on. If you don’t have time to shop and want simple meal-prep that leads to a good meal, a food subscription service may be perfect for you.