I did not realize you where using ASP, the calculations where writen for PHP. In asp the calculations should be:
Set the TotalPrice calculation to:
(([Price] * [Quantity]) - (([Quantity]>6 &[category]='1')?(([Quantity]-6)*18):0))
if you want to display the savings, create an new calculation called savings:
([Price] * [Quantity]) - (([Price] * [Quantity]) - (([Quantity]>6 & [catagory]='1')?(([Quantity]-6)*18):0))
You will either need to crate a second category, or add another column for named DiscountAmount you would need to add that column to the database as well, and change the calculation to:
Set the TotalPrice calculation to:
(([Price] * [Quantity]) - (([Quantity]>6 && [category]=='1')?(([Quantity]-6)*[DiscountAmount]):0))
if you want to display the savings, create an new calculation called savings:
([Price] * [Quantity]) - (([Price] * [Quantity]) - (([Quantity]>6 && [catagory]=='1')?(([Quantity]-6)*[DiscountAmount]):0))