Symptoms would include hair loss, excessive itching and/or scabbing caused by itching. That said, there's no reason to treat something that may not even be an issue. If you haven't seen any symptoms, there's nothing to treat, and treatment can be very hard on a dog, so it's definitely not something you want to do for no reason.
If you do see the symptoms, you need to get your dog to a vet for treatment. I realize you don't have a lot of money, but please do understand that it's very important your puppy gets all of her necessary vaccinations, exams, and treatment for any issues done by your veterinarian. There are options for low-income owners to get affordable vet care for their pets.
Something to be aware of is that dilute dogs do tend to have skin issues, many times related to food or environment allergies. Because these issues may present themselves similarly to how mange would, it's important to have a skin scraping done in order to know whether or not it is mites or something else.
Also because of this potential for allergy and skin issues, it may be best for you to switch to a higher quality food, that way you may be able to prevent some common food allergies from presenting before they (possibly) become an issue.
Good luck with your pup.