Amazon Mechanical Turk is a service that lets you make money online through doing paid microtasks. Each task is something simple that requires human interaction like rating search results, checking for the right spelling on search terms, categorizing the tone of an article, or even basic translating. You can do these tasks from anywhere you want and make money online from the world’s largest e-retailer.
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).
Even though risk-taking is a generally rewarding strategy in your 20s and 30s, it's also a good idea to diversify your efforts. Don't build up just one skill set, or one set of professional connections. Don't rely on one type of investment, and don't gamble all your savings on one venture. Instead, try to set up multiple income streams, generate several backup plans for your goals and businesses, and hedge your bets by looking for new opportunities everywhere. This will protect you from catastrophic losses, and increase your chances of striking it big in one of your ventures.