I have added 3 custom fields to the Opportunity Product section, all of which are set to currency and have a 14 character limit with 4 decimal places. I am trying to build a 4th formula with the following to equal "total price" (also a currency with the above):

Dollar_GB_Cost__c  *  Standard_Price__c  =  List_Price__c

What am I doing wrong here? I am new to salesforce and trying to mess around with opportunity pricing based on a cost (usually in the $.50 range) x standard cost = list price/sales price.