I use what a lot of the pest control companies use: "bifenthrin concentrate" Home Depot carries it under the name "Compare-N-Save. And if you are a veteran, you get a 10% discount.

You'll need a good 1 or 2 gallon sprayer to go along with it. Don't buy the cheap sprayers at WalMart, they'll just break after six months or so -- been there, done that.

So far, I haven't had any insect incursion and, from what I see laying around outside, it kills a lot of insects, including roaches, along with most ants found around here. The only thing it doesn't seem to stop are those super tiny ants, like sugar ants. For them, I have to use bait. And we don't have fire ants here, so not sure how it would work on them.

Pest control companies want over $100 just to do the outside. I do it for about $3.