Walmart offers the Northwest 16-LED Soft Light Illumination Floor Mat
, model no. 82-16LED, for $12.38
. Opt for in-store pickup
to dodge the $4.97 shipping charge. That's $7 under the lowest price we could find for a shipped mat and the best price we've seen. It measures 16" x 24" x 1" and features sensors to turn on when stepped upon and auto-off after 60 seconds, and requires three AAA batteries (not included).
charges the same with free shipping for Prime members, although its listing is currently temporarily out of stock.