I just recently got a very matted shitzu from an elderly lady who could no longer take care of him what could?

I do to get rid of the severe matting myself without spending a fortune? He is a very loveable dog and great with my 4 yr old and 10 mth old but due to cost I didnt know what it would cost me to get him cleared up? Im a dog lover and would like to help him myself as much as I can, as for my kids!