Buy from rockauto, here's a coupon code I received last week. 129222958120312182
If you ship to a business address, shipping is cheaper too.
I already purchased my qty 6 NGK iridium spark plugs from the Toyota dealer and I am prepared for the recommended 120K mi change. I also purchased qty 3 eBay Denso OEM ignition coils made in Japan (supposedly lifetime warranty) and plan to eventually install them on the back-side against the firewall.
My current reading is 98K mi and I will swap out the easy front three ignition coils next weekend. I will run the new coils to 120K and then move them to the rear firewall side during the spark plug change.
If a coil goes bad between now and 120K then it is RockAuto Denso coil at $53 a piece.