Creating IF formula based off drop-down list selection

I understand Excel basics, but this one has me stumped. Ideally, I would like a cell to multiply the value from another cell based on the selection made from a dropdown list. So it would go something like this: Dropdown list is in cell A1. "Promotion XYZ - 20% off" is the selection made from the list. Cell B1 displays the standard retail value of a product at $100. Cell C1 is where I've been trying to build an IF formula that would display the promotional rate, which would ultimately be B1*0.2 ($80). There are multiple promotion selections to choose from and varying standard retail values. These are quotes that will be sent to customers and I would like my team to be able to make selections and have the sheet do the math for them versus relying on them to do the math themselves. Any help is greatly appreciated!!