Thank you I think I will try that!
It could be many things such as Scabies, Atopy (skin allergy), food allergy dermatitis, flea allergy dermatitis, bacterial or yeast skin infection and more.
Since money is an issue you can try bathing your dog with Malaseb shampoo (available online) twice per week. Malaseb is effective for bacterial and yeast skin infections that are secondary to allergies. It may help slightly with the Scabies and Flea allergy temporarily by mechanically removing the mites or fleas. The shampoo may provide enough relief for your dog until you can take her to the vet.