Avoid Sales Tax (Sort Of)

If you have a Discover Card, after logging onto your online account, you can then access ShopDiscover.  And what pray tell will ShopDiscover get you?  Anywhere between 5% to 20% cash back from select retailers.  Here's how it works:  Let's say you want a Nano from Apple.  Log onto Discover and go to ShopDiscover.  Select Apple (they are one of the dozens of retailers).  Shipping is free, and because you are going through ShopDiscover, you are going to get 5% back.  So if you have to pay sales tax, it's kinda like getting a rebate on your sales tax...