My client sells seminars, which is non-taxable and CD's, which are taxable. She sells maybe 8 CD's and a couple bundles. Three of the CD's are new. The promo is buy one of the new CD's and get each additional new CD at 50% off. All these new CD's are the same price. Since this only applies to the new CD's and this promo can't be mixed with the old CD's, and there's no coupon number to apply - I made a column value representing the on-special products. Depending upon the total of this column value, certain flat rate discounts are applied. This all works perfectly, except for the tax.
If you see my screen shot, the cart shows two cd's that are part of the special with the flat discount being taken off. It also has a seminar in it. The tax should only be based on the two cd's, which it is. But it should be based on the two cd's minus the flat discount, which it isn't.
What do you think?