I’ll give an anecdote that I experienced just now. I bought a computer component, but I had to dig through the “other buying options” to find it on Amazon. The default recommended listing had a price of $207, delivered to me by 2 October. The listing I eventually found was priced at $206, delivered by 28 September. So it cost less and would arrive sooner, the only difference is that it was a third-party seller and not Amazon.