It's taking $40 with amex promo as well so effectively $70 off.
Follow this link for savings from amex,http://forums.dansdeals.com/index.php?topic=92831.0
Only black gives you $40 off on the $79 model, and if you place both the black and white in cart you will only receive $30 per kindle readers plus $30 student saving so best is to buy black device separately.