AFAIK, real estate falls into that category. (To be fair, I was researching, not actually attempting to buy online) Certain categories of food would also fall

AFAIK, real estate falls into that category. (To be fair, I was researching, not actually attempting to buy online) Certain categories of food would also fall into that category, especially if you're not in a major city (e.g. fresh seafood, delivery for some types of cuisines). If you're looking to find some blatantly obvious material good which would be easy to sell online, in the hopes of making a quick profitable business, I'd reckon statistics are against you.