New releases at $48, plus a reasonable chance at getting an additional $10 Reward Zone certificate with a pre-order.
Do that three times on a new release and you've just paid for the membership, if you've done nothing else.
I rarely buy any games except at Best Buy for the reason of GCU. During BF, I picked up 9-10 games, all 20% off of the BF prices, which was a no-brainer to do.