Black Flag Spider and Scorpion Killer Aerosol Spray
For the best deal in a spider killing spray, get Black Flag Spider and Scorpion Killer Aerosol Spray. Made of a synthetic pyrethrin in a mineral oil mix, this spray kills as well as anything else and lasts up to 16 weeks of residual effectiveness. If we were giving a bang for the buck award for a spray can, this one takes the prize. Realistically, every other spider killing spray kills spiders just as effectively, but Black Flag costs less then any of the other spray types on this list. It is cost effective to use, lasts long and you won't go broke if you need a couple of cans for a major spider infestation.