Does your site have to be the most fancy thing to make money? To what degree should you stress over your website’s design before going live?
Design DOES matter, not because of how pretty it needs to look but what it communicates to your reader. Ugly, but functional, is actually not ugly at all. All the people saying “design doesn’t matter” are misunderstanding the point of design. (HINT: it doesn’t mean load up the most bloated JS-heavy super-theme you can find.)
With that said, it also depends on what you’re selling. If your website is a simple blog intended to look like an honest one-man-show posting affiliate links for marijuana periphernalia, that’s going to have a very different design requirement than one intended to sell wedding photography.
Design = communication, not flash. Therefore…Amazon, Reddit, Facebook, and whatever other sites the commenters mentioned are actually VERY WELL DESIGNED. It’s too bad most clients and low-level freelance designers are wasting their time copying the latest design trends instead of actually understanding what design really is. True quality design more closely follows timeless UI/UX principles, not latest graphic design trends.