Morph Collector
Extremely Obsessed
That's definitely not the case everywhere. Here in the Chicago suburbs it's not sold in grocery stores. The only source is an ice company, and they sell dry ice 10 lbs minimum for $7.50.
You may use a few lbs of that for killing mice but within a few days all that extra will be vapor.
Bummer, thats still $.75 a lb. I would sell 9 lbs to some kids in your neighborhood so they can blow some stuff up (for $1 a lb even, they don't know the difference). That way your CO2 would be free.