This discount should show up when you review the cart the first time before you go through the payment gateway. There was some discussion earlier in the thread about some of the freebie items not working how they should and others working fine.
The in-cart freebie is the Ricardi hair. I did wonder about that, so I tried going through with my second-choice freebie (the feather hair) but it didn’t work either.
As noted I’m not a Platinum member and so I’m only getting a 50% discount. If I were getting the 70% discount the cart would be at $21, well below the $30 threshold. When I added a DAZ Original of $10 value to my cart, et voila, the Ricardi hair was discounted.
I, ah, think I found your bug, guys. :D