Comparing a cell to another cell within a range

Hey everyone, I am stuck. I am trying to determine if an advertised price is lower than the list prices and return a msgbox if it is true. The list prices for each product are static in cells B8:B29 and the advertised prices are per company and are in C8:c29, D8: D29, etc and correspond to the same row as the list price. How do I compare each advertised price to the respective list price and return a msgbox if the advertised price is lower.

I have created code to do it one column at a time just comparing the activecell to activecell.offset(0,-1), but it is tedious and there has to be a better way.

Thanks in advance for your help!

There is a bit I do not understand. At what point is the message box to appear if the values are already there?

The values are gathered from web data, consolidated in a separate sheet, then transferred to this one to maintain a consistent formatting. There will be close to 30 companies with 21 products to check. I want to be able to refresh all of the data and a text box to appear with the company and product that is below list price.

I'm sorry this is a bit confusing. The data is continually updated and too much to monitor or have just conditional formatting but if a text box appears then you are alerted to it and can investigate further.

Hope this helps!