I think in our area full page ads range from 1500-2000 a month. I agree with what people said about the bigger ads for better exposure, particularly in the carpet cleaning section. Air duct and resto work sections would require a smaller ad due to less competition.
We have never run a full page ad. However in the yellow pages we run listings in bold type under specific towns and or counties. The people looking for someone local go right for those ads. Those ads are just the name of the company and a the phone number. Those have worked with decent success for us. Plus it helps on fuel costs and to target market to certain income levels.
We run ads in individual flyer's that are mailed separately by a company around here (you know your ad on one side and the missing child one on the other). Sometimes it might have another company of no relation to what you do on the other side, but most likely just your ad. We have done ads in Val-Pak....with not nearly as much success. Val-Pak seems to have 20-30 small flyer's in one envelope and in there seems to always be 2-3 other carpet cleaners in the one envelope. So before the ad arrives your ad is already up against the competition, especially on PRICE.