I have an easy one here, I think -- but my track record working with picklists in formulas is not so good.

I'm creating a custom field for Quotes to calculate sales tax.

I have a picklist field Sales Tax with two values: CA and Out-of-State.  Tax is 9.75% and 0%, respectively.

I'm trying to reference that picklist val to calc tax on a qoute's Total Price.

ISPICKVAL(Sales_Tax__c, "CA", (TotalPrice * 0.0975), 0)

The error I get is:

Incorrect number of parameters for ISPICKVAL(), expected 2 received 4.

I'd appreciate any help!