I am having trouble figuring out how 2 for 1 sales work here.

Do I add both items to my cart, pay for them, and get a refund on one of them?

Or do I add just one item and then wait for a coupon?

Because when I add both items of identical price that are marked on sale 2 for 1, when I go through checkout, it wants to charge me for both of them.

So could someone please tell me what the procedure should be?

Thanks

---

PoserPro 2014, PS CS5.5 Ext, Nikon D300. Win 8, i7-4770 @ 3.4 GHz, AMD Radeon 8570, 12 GB RAM.