When checking out at product table times or before the conference, to get the discounts, see this page for all the product sale prices and links.

Click on a certain link and it will take you to the particular product page.

Add items to your shopping cart. If you want items from different categories, you may order them all in the same order. Click "Continue Shopping" grey button to get back to the store. 

Select any other type of product and add to the cart. Continue on with this process. Once you have all your products in the cart, you may begin adding coupon or "DISCOUNT CODES"

You'll notice on this check out page example, I added one of each 'coded' product to the cart and inserted each of the different codes in the DISCOUNT CODE BOX, pressing Apply after each code entry.

Hope that helps...