We've all used price comparison websites. As soon as the car or home insurance renewal comes through, for example, we jump straight on one to find out if we could buy cover cheaper elsewhere. We search to see if we could get our utilities cheaper and we even use them to find the cheapest place to buy a product that we're interested in. Price comparison websites have made us all financially savvy. Have you ever wondered how they actually work, how do they know the prices of everything for instance and how is it so readily available? Read on to find out.

Ever Compared Price Comparison Websites?

There are plenty of price comparison sites on the market and you would be forgiven for thinking that the method they use to collect data is scientific. However, if you have ever compared them you might have found discrepancies between pricing information. Often, the same item can have different pricing information on competing comparison sites. These differences occur when websites use different methods to collect their data.

How do they Collect Data?

There are two main methods that websites use to collect pricing information. One of them is known as crawling. This involves creating software that visits sellers pages and compiles all the pricing information through the analysing the HTML. It acts very much in the same way that Google does when it analyses HTML to search for the keywords that you have entered. There are problems associated with this method in that merchant sites can often use different descriptions for products, so it can be difficult to gather cohesive information. This is why many price comparison sites use data feeds.

What are Data Feeds?

Data feeds are files that are created by merchant stores that they pass on to price comparison sites. These files are easier for the site to analyse and they are often more reliable than information gathered through crawling. Having said that comparison sites are at the mercy of the merchant, they could choose not to supply any information and if they do how up-to-date the files are is down to them. For this reason, many comparison sites looking to gather pricing information have to use a combination of both crawling and using data feeds. This can often lead to contradictions between the sites.

How is the Information Presented?

When you have completed a search for a product using a price comparison website you can usually sort the items listed by factors such as price, positive reviews, or delivery charges. Of course, initially, the results will be presented in a way in which the comparison site want you to see them. Everytime you click through on a link from a price comparison website, they charge the merchant that you visit a fee, this is how they make money. Of course, all sellers will be prepared to pay different fees and so those products you see at the top of the search results are likely to be from those merchants who are prepared to pay more. You should always sort a list once you have generated it to check that you are genuinely seeing the lowest price.


Price comparison sites can save us lots of time when we are trying to save ourselves some money but we do need to be careful about trusting all the information that they supply. In order to discover the cheapest price of a product or service, you might need to do several searches on different sites to be on the safe side.