If you have experience with marketing, SEO, or a knack for getting people excited about the products and services you use on a regular basis, think about refining your skills and putting them to work making money online as a small business marketing consultant in your region—especially if you can become a local SEO expert and can help local clients rank higher in their search results.
Mechanical Turk: Amazon's Mechanical Turk is a resource for doing human-intelligence tasks, or as the site commonly refers to them, HITs. You get paid a very small fee for any given HIT and you'll need a good deal of volume to make a substantial amount of money. But it is a resource you can use in your spare time to generate a small income online.
Blogging is something that requires patience, persistence and discipline. It may mean writing everyday for over a year before you really start to see any money from it. There are exceptions to the rule, but from my dealings with other bloggers, it seems to be pretty common to spend one or even two years building your blog, your brand and your authority, before making any serious amount of money.
Learn then selling guidelines. Each marketplace has guidelines that define what you can and cannot sell. State and federal laws also impact what items are prohibited. In general, you cannot sell alcohol, weapons, service contracts, animals or event tickets. Also, while not always prohibited, you may find restrictions on how you can sell items in some categories, such as art, gift cards and coupons. eBay, Craigslist and Amazon publish these guidelines on their websites.
How much will you make? I think my best month with Google AdSense was almost $5,000 over the last ten years. That amazing month blew my mind since it was actually near the beginning of my blogging journey. When you go from making zero to $5,000 in a month, that will rock your world. For me, it also got me even more excited because I knew there were other ways to monetize.