Looking for a deal on a smoke & CO2 alarm.

Prefer local store as mine has died and I don't like to run the heat without one. I have locally: Home Depot, Lowes, Office Max, Office Depot, Walmart, HEB, Target, Harbor Fright Tools, Walgreens and CVS.

Extra bonus if it's Walgreens, CVS, or Office Max as I have gift cards for there.