Sell hair, plasma, or other body parts/fluids. Long, healthy, untreated hair can be sold for a variety of purposes (including high-end wig- and extension-making) and earn you anywhere from several hundred to several thousand dollars depending on color, health, and length. Plasma can be “donated” (for compensation) provided that you are old, healthy, and heavy enough to qualify. Sperm can be donated, but you usually have to know (and be able to document) a fair amount of information about your parents as well as your medical history to be eligible. But be wary; for example, donating eggs is often touted as a fast, high-profit medical procedure, but the process is actually requires that the participant undergo hormonal and medical treatment, receive regular checkups and ultrasounds, and abstain from sex and intoxicants, all of which take weeks or even months before the eggs are even eligible for removal. The removal process itself is invasive and lasts about 30 minutes. Consider your options very carefully before taking on anything like this.
The Learning Annex (212-371-0280, learningannex.com) offers more than 8,000 courses each year, from how to be a matchmaker and how to flip houses to how to be a "Real Cougar Woman." If you have an idea for a class ("How to Make Money Without Really Working"?), send an e-mail to firstname.lastname@example.org. For noncelebrity teachers, they pay a percentage of the revenue. The average class costs $44.95—so enroll 30 students and you'll make $150--$200.
Websites like Survey Junkie will pay you a decent chunk of change for the low-maintenance, borderline mindless task of completing surveys. Companies want to understand consumers better, and one way they do that is by compensating survey-takers. Most surveys pay between $0.50 and $1.25, and many of them take less than 5 minutes to do. You can read our full Survey Junkie review for more info.