There are certain reasons why some of the sites that specialise in comparing products and services online are more effective than the others. The first of these is that certain of the sites are sponsored by the very institutions that they are comparing. Therefore, you might find that the first three to five results that appear after you have made a particular product search, are, on some sites, references to sponsored listings rather than to the best deal that is available online. Care should be taken to examine the websites terms so that you can be clear about whether the top results from your search are indicative of the best financial deals or, rather, a reflection of a sponsorship arrangements between the price comparison site and the particular retailer or product provider.

A second reason why you might find a discrepancy between the top deals offered by more than one site relates to the number of online providers that are accessed by the sites search. Although it is not conclusively the case on all occasions, it is certainly to be more likely than not that a site that accesses a greater number of internet suppliers and providers will access the best deals. If information is given by a website as to the number of individual sites it accesses when it compares prices, check other similar sites against this and make your own comparison of the prices.

In a similar vein, the percentage of the online market that is covered can have a direct impact on the quality of the results of a given search. If, for instance, a particular comparison site did not access a particular online provider, for whatever reason, this would impact upon the results of a comparison to an extent proportionate to the size of the excluded provider.