Walmart offers the
Kidde Smoke and Carbon Monoxide Alarm, model no. KN-COSM-BA, for
$20.43. Opt for in-store
pickup to avoid the $5.97 shipping fee. That's $4 under our mention from last June and the lowest price we've seen. (It's the best deal now by $5.) It features a low battery warning, test reset button, and Smart Hush, which temporarily silences nuisance alarms