Some products display an (a) MSRP (the manufacturer's suggested retail price) right above the (b) advertised price to show you the savings the merchant is offering on the item.

Notice the (a) line below the advertised price. It gives you an overview of how much a product is discounted. You can see exactly where that savings comes from by (b) clicking on the arrow to the right of the line.

Doing this will display:

The Savings: The amount the merchant is discounting the product compared to the MSRP. You’ll see this both as a percentage and a dollar amount.

Discount Dollars/ Additional Discount: The additional savings you get on the product as a result of the current promotion. Again, you'll see this as a percentage and a dollar amount. Below that, you'll see how long you have to take advantage of the promotion to get the added discount.