My Dad phoned the local Fire Department. They came, & installed 5 free fire alarms. City-funded program.
Almost nobody asks for em, so they were glad we did. 
Neat.
Free stuff is fun. We got free trees to help shade our house from our electric company.
I got some free Oak trees several years ago, from TN Dept Forestry.
1/2 died, but the others are doing fine.
Usually FD will give out free batteries around Daylight Savings time changes, for those smoke detectors.
I imagine it only takes one residential fire with smothered children to get a firefighter really excited about the benefits of smoke detectors.
Our local fire department ran a program a few years back (before I lived in this city). Show them a properly installed smoke detector with a working battery…get a coupon for a free pizza.