I don’t mean to be rude but “selling things on craigslist” shouldn’t be on the list, I mean that’s like saying to get rich you can just sell all the expensive stuff you have laying around from being rich already. Maybe steal a bunch of bbq’s and sell them on craigslist might apply. Also I don’t see how “my cousin has a job” is a vaild way to make 100 really quick in a day… I have a job too, is that some secret trick, getting a job? a good way to make 100 a day is selling plasma and sperm for girls eggs can get you several 1000. or just find some people that look like they have money and scam them.
Regardless if you need to earn some fast cash or we're just talking about making money in the grand scheme of things, there's an important psychology that needs to be mentioned before getting into the strategies. If you study Freud's model of the mind, you'll discover the Psychic Apparatus. It's the three-part construct in your mind that controls all of your behavior.
Use your credit card’s cash advance feature. Some credit cards will allow you to withdraw a certain amount of cash by using it at an ATM. This can help you come up with cash in a hurry. However, the interest rates on cash advances are usually much higher than the credit card’s usual interest rate, meaning that you will eventually have to pay more.
Become a babysitter if you are good with children. There are websites that will connect you with people who need a babysitter. To get hired by people who do not know you, it will help to pass a CPR class, or to have a special talent or expertise for entertaining children. However, you might be able to make money more quickly just by babysitting for people you know, or by having friends refer you to others who need a babysitter.