Many people associate online business with something that takes time to build, with a less than certain outcome. What kind of business to build? What niche to choose? What if it doesn't generate any money?
Buying an existing online business solves all those issues. You get some asset that is already generating some cashflow, with the niche already figured out, and with already existing customers. That's one of the best way I know to get into the online business game without having to wait for your business to take off. Even if you already own an online business, buying one can be a really quick way to expand your portfolio and generate more income, which I what I did with my own portfolio of online businesses.
There are of course several things you need to figure out before buying an existing online business. How to actually select a good business to buy? How to get financing if you don't have enough money to buy a site? And what to actually do with the site once you bought it? This is all things I figured out over the years while building my own portfolio - and on this page I share all my experience on the topic.