I got the HD10 last night for $90 using
this slickdeals thread. If the deal is still active (it's still up on the slickdeals home page), you need to link (or already have linked) a certain type of Amex card or a Citi ThankYou card, and pay with at least one reward point.
I had both cards and linked them last night. The ThankYou card didn't take, but my Amex green card eventually did, and got me that additional $30 off (that's additional to the $30 off sale) after applying the promo code on the next page during checkout.
There are opinions on the HD10 itself within that slickdeals thread. Seems heavy, large bezels, more RAM and ppi than the other smaller Fires on sale.