[header] How to navigate dog classified ads [title] Be on guard with free classifieds. [step] Before you start skimming through classified ads, check whether it's free to post listings or if a fee is charged to do so. Expect to find puppy mills, backyard breeders, and scammers advertising dogs on free sites. 
Remember: their chief concern is making money, so obviously they're going to spend as little as possible and certainly take advantage of free advertising. [substeps] This doesn't mean that sites that charge money to post listings are 100% free of untrustworthy sellers.