Home Depot has a fire safety event. Kidde twin pack fire extinguishers 3.9lb each (-- The given link is broken --) and fire extinguisher / carbon monoxide detector set for $29.97.
Comparable size at homedepot is $19/each.
There are a few other sets.
Kidde Pro 2A10BC fire extinguisher twin pack (-- The given link is broken --) $69
Twin pack smoke/co combo alarms (hard wired set and battery set) $89
And a few other items.