http://www.homedepot.com/p/Ortho-Hom...2#.UdsKkaye2So

This $6 jug has kept my house bug free for 3 years... I find an occasional dead bug in the foyer and slightly higher numbers in the garage, but alas they're already dead. I spray around the base boards on the 1st floor, and across the openings of any entry way. Seems to do the trick for me...

If you're dealing with an actual infestation, that's a different story, but just a few spiders? I'd think you can knock it out on your own easily.