We pay $60 each visit, not on a contract, and they recommend a treatment every other month for our 2000 square foot home. They spray inside and outside the home. Our cost is just for basic prevention services for normal bugs (ants, cockroaches, bees)
But it also depends on what you want them to treat. If you have an actual infestation, or something that isn't really "normal" (mice, rats, termites) the price is a lot higher.