Update: If you buy $30 on a single purchase (two readers, perhaps?), you also get a $10 gift certificate to use on a future purchase at RadioShack.
This is an in-store deal only and only at selected Radio Shacks. No doubt they are closing out on these, but if you have been wanting an eInk reader for your Nook Books, perhaps one that you won't be as upset if the kids break, this is a heck of a deal. You can search from the online product page for the Nook Simple Touch and see if a store near you has these in stock. One trick, I found, was to increase the search distance to 50 miles, as the default 5 miles often won't even find a store in the same zip code. In our city, it appears that only one store location has these in stock and I suspect more and more will sell out as the sale progresses this week.
Pair this with a cover from Barnes & Noble, all but one of which are selling for $15 or less online and in-store right now (that high dollar one is also under $20), and you can have a perfect Mother's Day Gift for less than the cost of dinner out for two.