i added session new session as UserTax but how does formula work?
Example:
I m looking at something lik this:
PRODUCT | RATE | SUBTOTAL
XYZ | 100 | 100
ABC | 100 | 100
SUBTOTAL: 200**
Discount 5% on subtotal (static value) : -10 *
Sales Tax $_SESSION['UserTax'] (ex: 5) so 5% on subtotal after discount ie 190 (200**-10*) : 9.5
Insurance 0.3% on Subtotal (200): 0.6
TOTAL: 200.1 (200-10+9.5+0.6)