This is a hard question to answer because it really depends on what you want to accomplish. When someone asks me that question I have to ask them by quick do you mean easy? The answer is usually yes, I mean easy. Easy is relative. What's easy for some may not be easy for others. There are quick ways to earn money online. Whether or not the income is significant or long lasting is another issue.
There are simple, easy and relatively quick methods available to earn money. Some of the more popular ones include paid surveys, chain letters, reading emails, autosurf programs. You can make some money with any of these programs but I can assure you it won't be a lot, the time you have to put into them isn't worth the return and when you stop the program you stop making any money.
So a better question to ask yourself is are there better quick ways to earn money online that will provide an opportunity for significant income that is long-lasting? The answer to this question is yes. Quick money in this case doesn't necessarily mean easy money. If you really apply yourself and add an ounce of luck into the equation it is possible for you to be earning money within 30 to 60 days of starting your online business. If you want that business to grow into a full time income producer then you will have to work it a lot harder and for a lot longer.
The easiest way to get started with an online business is to become an affiliate marketer. You find a market that is hungry for a product, you find a product that is already available for sale that will cater to this hungry market, you create a simple webpage that will presell your visitors, your drive traffic to this site, visitors go there and click on a link that takes them to the vendors page. Once there they will hopefully buy the product and you get a commission.
How easy is this, really? In concept it is very simple. The hard part is driving consistent traffic to the site and creating a captivating enough presell page so your visitors click through to the main sales page and purchase from you. Once you have accomplished this you will have a money making site for years to come.