Best Buy offers the Rocketfish Clip-On LED Light for eReaders, model no. RF-ERCL-02, for $2.99plus $1.99 for shipping. (Free in-store pickup is also available.) That's $17 off, tied with our mention from last week, and the lowest total price we could find. It features two light settings and an adjustable gooseneck.
Update: It's now available for in-store pickup only.