Trying to add THREE sets of THREE IF statements. Maybe there's a better way to do ti?

I have three products, and each of them has 2 price sets: Retail and Web.

I'm trying to make it easy on the client so that they can just choose "web/retail" from a dropdown and then "8oz/gallon/25lb bulk" from a dropdown and have the prices calculated automatically.

Here's what I have right now in the Price column:

=IF(F13="Web", IF(E13="8oz", (3.19*C13), IF(E13="Gallon", (29.99*C13), 
IF(E13="25lb Bulk", (82.99*C13)))), (IF(F13="Retail", IF(E13="8oz", (2.2*C13), 
IF(E13="Gallon", (29.99*C13), IF(E13="25lb Bulk", (82.99*C13)))))))

I have this working right now, but I'm about to add another IF and I cannot seem to figure out how. I need to add another selection for "deposit" so that he can select "web/retail/deposit" and deposit would mean he is depositing inventory and so SUBTRACT the COST (another set of numbers) of those products.

How would I go about adding another IF statement depending on a new selection "deposit"?