It has always been the case that shoppers have been expected to know what they want when it comes to buying online. Searches and navigation have always been geared around typing the exact product name in or refining by brand and general item characteristics. Price comparison sites are very useful tools when you want to find the cheapest prices and where to buy the product you actually want, but they are hopeless in helping you browse around.
I often see bookshops as a really good example of how to try to help people find what to buy as it is not often someone enters these places knowing exactly what they want. As soon as you enter a bookshop, you see a large section dedicated to "bestsellers" to see what are popular with other people right now. You will also see a "just released" area where you could find something new and exciting which no one has really discovered yet and thus be one of the first. "Editors Picks" are there to give you some encouragement that a known expert has rated those particular books and help justify your decision to purchase. After that, you can then choose to browse by topic or author in the rest of the shop.
This fascinates me as you see it all the time across the web anywhere there is a large amount of content or range of products that you need to encourage people to find something they like within. Often you also bring judgements and perceptions to bear on the problem from your own individual experience. In the case of the bookshop, I will be thinking about books I have seen advertised elsewhere, reviews I may have read where a magazine or expert rated it, and any recommendations from my friends. I will use all of these to help me browse and find something that I think may interest me.
So, if you take all of the factors above as key in helping you find what you want - then the real question is
"why would you only ever care about something that showed you the best price?"