What does the discount for accessories mean on the Sparkle Savers Plan? How can I use it?

That's an important thing you should be aware of ;)

As part of the Sparkle Saver's Plan you're a premium member and entitled to special discounts and offers. After registering on the plan, you will receive an email with a coupon code that will provide you with a discount on all the accessories in the site (in addition to any existing discount/promotion). Use the code you receive in the cart.