Selling blood….there are very few companies that buy your blood. #1 reason being MANY people willing to sell their blood are not the type of people you want to receive their blood, ie drug addicts (not everyone). And if you can find a company willing to buy your blood you can only give it every 56 days (for whole bood). The most common blood product that is bought is plasma and you can only do that every 28 days (in New York state …which won’t buy blood anyways).
If you are particularly good at somethings, say map design, capable of creating a series of video lessons, you can become a tutor at SkillShare. You’ll be in good company with folks like Seth Godin and James Franco among others. SkillShare tutorials and 30 days teaching challenge will help you create a winning video tutorial. Your earnings will depend on the popularity of your course, but even low attendance will let you earn some decent money.