Upwork: This website offers a great marketplace for selling just about any professional service. You don't need a merchant account, website of your own or anything else for that matter. All you need to do is be able to provide a high-quality service at a reasonable price. But be informed, you will have to compete with many others that are constantly bidding on open jobs.
Before I talk about some of the methods for making money online, I wanted to address the role of pain versus pleasure. Every decision that we make in life is weighed on a pain-versus-pleasure scale. We will always do more to avoid pain than we will to gain pleasure, plain and simple. However, this is also what holds us back from succeeding in any endeavor.