I am really worried about my dogs ears he seems to have a tar like substance down them and I don't know what to do, as I am unable to get out of the house to the vets and I can't afford the cost of calling the vet out.

Will your vet take a lot a swab of the substance in your dog's ear? If so, get a Qtip, dig it out-don't worry, you cannot hit the eardrum-, and have someone take it up to the clinic. It really sounds like a bad case of ear mites which can only be cleared up by prescription meds from a vet. If your dog is an established patient, it's likely that they can prescribe something just by seeing the swab.