Bearded Dragon will not eat? (READ ALL)?

The black spot could be his skin dieing. Call your vet's office tell them you need to come in for a recheck and see if they are willing to work with you on a payment schedule. Most will. He could have an infection that is spreading through his system. I don't want to see him die as much as you don't want to see him die. You said that you would do what it take, well it's going to take another vet visit to make sure that survives. I wish you all the best and hopes he ges better.