If you walked into Wal-Mart to purchase a camera and the sales person told you the camera you were interested in was $300 and then he offered it to the next person in line for $200, you would probably be aggravated.  If the clerk explained that your higher price was based on the fact that he thought you were a very interested buyer who was ready to make a purchase, while the other person was not a serious buyer, you might be even more outraged.

Yet, that is exactly what is happening with online shopping. Online retailers are using cookies to track your moves. Although cookies are relatively harmless and unobtrusive, they show the retailer exactly which items you have looked at and how often you have view them. Retailers can also use click loggers, ad sites, and computer-generated statistics to track your shopping.  If you look at the same item several days in a row, the retailer might decide that you will soon be ready to buy and raise the price.

This happened to me recently, when looking for a bird feeder for my husband for father's day. After several days a looking at the item and mulling the purchase, the price of the bird feeder suddenly went from $42 to $51.

This is what is commonly referred to as dynamic pricing which is, in effect, changing the price of a good based on what the retailer thinks a buyer is willing to pay. If you think about it, you realize that dynamic pricing has been around for eons.  In a street market hundreds of years ago, a person who was a better haggler may have paid less for the same item as someone who simply agreed to the first price given.

Today's online dynamic pricing is the practice of charging consumers different amounts based, not on their haggling ability, but on their characteristics as consumers. Evidently, as long as this does not include discriminatory criteria, like charging someone with blue eyes more than someone with green eyes, this is perfectly legal.

After all, airlines have been doing it for years. They typically charge more for flights that are popular with business travelers and they also have complex pricing schemes to fill unused seats. This year the St. Louis Cardinals introduced dynamic pricing for tickets to their ball park. This allows the Cardinals to charge more for "hot" games on popular days. A recent look at ticket prices showed that an infield pavilion seat for a Saturday night game was selling for $42. The same seat on a weeknight might be a little as $13.50. It was said that a few years ago, CocaCola did a test with their vending machines that charged more for soft drinks when the outside temperature rose.

Dynamic pricing doesn't always go against you. For instance, it might be advantageous if you are booking a last minute flight or looking for a cheap ticket to the Cardinal's game. .,When dealing with dynamic pricing online, however, the instances that I saw in my recent shopping have all been leading toward higher pricing. There is, however, something that you can do to counteract this when it goes against you.

When they raised the price on my bird feeder, I decided to check out the price of the feeder using another web browser that didn't have a cookie identifying me. Sure enough, the price was back to $42. I was able to see the two different prices at the same website side by side when using two different web browsers.

You can do the same thing, just download a new web browser like Firefox  (www.firefox.com), Chrome (www.google.com/chrome), or Opera (www.opera.com). These are all free.  Then visit the website in question and look at their prices without logging in or giving any personal information. If you have been using one of these alternative browsers and want to use them for a price comparison, you should clear your cookies before you start your price search. A setting for doing that is usually found in the browser's Tools menu.

Dynamic pricing is not going away anytime soon. It looks like it will be a vital part of both off-line and online commerce for years to come. So get used to it, but don't get taken in by it.