Thought I'd note that I had used the code to get Deus Ex at $16.24 with Shoprunner with my account. A friend had hit hard times and couldn't afford to get a copy and I wanted to give him one. But.. code used, couldn't use again. F.
Until... I created a new account with a new email address. I used the same payment method, same physical address information as my other account, same phone number, even same Shoprunner account for free shipping. The code worked to buy him a copy. So, I suppose, you could create another account to buy a second game or whatever discounted.