Cheap seo, exploring in depth
An alternate reason can be that their labor and other costs is less than their competitors thus giving them an option of providing the same service at a much lesser price. Another approach can be hiring of freelancers or newly established firms who would be willing to provide the same service at a lower cost. This would have double benefit for the client. Firstly you are being charged less and secondly they would be at your disposal all the time. Additional benefits accrue to you at a much lesser price.