Call around to vets, explain the problem. Call the humane society. Just start calling and explaining and eventually someone will help you out. You might consider putting out a plea on Facebook. Find a vet who will accept payments from people on Facebook, and have them pay him directly so they know it isn’t a scam. We recently had our dog put down. It cost us $80. The burial cost us $75, but you can bring your dog home and bury him in the yard.