Display 2 prices in the price field?

Client wants to display TWO prices in the Price area of products in a specific category. MSRP (manufacturer's suggested retail price) and "Our Price" Our price would be the price charged (plus applicable tax) when ordering.

Can this be done? If so, how?

What I would do in that case is to create a new custom field of the table "product" so that you can enter the MSRP for each product. Then, edit the file listing_price via the menu Display->Views and add the display of that custom field in there.