If there is blood present or the dog is lethargic, vomiting, or losing weight then please contact a vet and try to arrange a payment plan. If the dog is otherwise bright, make sure he is drinking plenty of water so as to avoid dehydration. Starve him for 12 - 24 hours to rest his gut, and then feed a bland diet (such as chicken and rice) until he produces a formed poop. You could also try giving a supplement of dog-probiotics to help colonize his gut with healthy bacteria. If he is not improving on this after a couple of days then he needs to see a vet.