Just purchased $3,000 worth of GCs for $2399.70 (no sales tax). Costco customer service says, "Let me save you some money. If you upgrade to Executive, $50, this purchase will just about pay for it because you'll begin getting 2% cash back begining with this purchase for whole your membership year, and we'll extend it another 2 months."

We shop at Costco quite a bit so I went for it. I've got about $2,000 worth of business Hyatt stays planned for January alone.