In case you're not aware, generally HD will accept Lowe's coupon if there is something there you want.
I generally prefer Lowe's though. I have a Menards and two HD within 5 minutes of me, but I find myself driving the 15 minutes to Lowe's.
Our re-pipe is almost done after a week of nothing due to weather. Had an electrical guy out for a walkthrough to see what is up to code and what it will cost to run some new lights/outlets. Some basic items but then some with ridiculous pricing. For 9 wireless smoke detectors they want to charge $998! 2 carbon monoxide detectors are $155.
After I wade through the BS, the wiring conversion from some old cloth covered wiring, install some outlets, and install some lighting does not seem too bad but I really don't know what things should cost or when I am getting ripped off. Google can only help so much.
I do not know what units are being quoted but they seem to range from $30-$50 for basic units unless you purchase Nest units which are $99 each. I don't think the company will shell out a ton of money on units but it seems like there is a flat rate fee per smoke detector.
I will have to look into the Nest alarms though. I didn't know they had a battery powered option...