Google Autocomplete is a feature built into the search engine that predicts what you're about to type and displays search queries to choose from. Those auto-complete search queries reflect the most common web search activity of all of Google's users (an insanely huge sample size, we can guess).
So how does that help you shop? Well, say you're searching for headphones. You've seen lots of people on the morning train ride rocking Beats by Dre cans around their necks, so that's where you start your search. You could go out any buy them today, but instead, you're going to use Google Autocomplete to help you.
Step 1: Go to google.com. (You'll actually need to head to the page, and not just use your browser's search box to see Autocomplete results.)
Step 2: Type "Beats by Dre vs" into the search box, and nothing else.
Step 3: Look at the searches Autocomplete suggests—"Beats by Dre vs Bose," and "Beats by Dre vs Sennheiser"—and check out some of the competition.
If you're after a certain make or model of tech or a coveted piece for your home, type it into Google, followed by "vs" offers up information about what other shoppers around the web have considered as an alternative. You could also try alternative searches with comparison keywords, like "Is a MacBook better than", to expand your product possibilities.
You just might find that, after a quick search, you've found a better product to suit your needs. Or you can at least say you considered it. Even if it only took 2 minutes.