You can now pick up the Nook Simple Touch for $79 and the Nook Color for $149. The sale runs until May 12 and Barnes & Noble will also throw in a free Nook gift bag with purchases of those devices (while supplies last). The bag doesn't look all that exciting, but hey, it's better than a plastic bag.
It should be noted that the Nook Simple Touch didn't sell as well as Barnes & Noble had hoped during last year's holiday season and the company recently started shipping the hot-selling $139 Nook Simple Touch with GlowLight, which earned a CNET Editors' Choice and is back-ordered until May 7. The Nook Color is also an older model that came out in 2010 and doesn't have the faster processor of the $199 Nook Tablet.
Barnes & Noble has discounted the Nook Simple Touch to $79 a couple times before, but that price point is the lowest for a touch-screen e-reader and matches Amazon's highly rated non-touch Kindle 2011 with Special Offers, which costs $79 and is ad-supported.
CNET readers frequently point out that you can get refurbished Nook e-readers at nicely discounted prices. A quick look at Google shows that most refurbished Nook Simple Touch units are selling for $79, though I did spot one for $59.99.