My dog has addison's disease and the monthly injection is about $200. -- Just about a car payment

Does anyone know of insurance or prescription plan that would help with this. most look like they don't cover pre existing conditions. I would really just want something to help with the medicine.
Re: pet insurance - pre existing conditions help!
I don't think you'll be able to find a pet insurance that will cover pre-existing conditions. A good website to compare the plans is petinsurancereview.com
Have you talked to your vet about learning to do the injections yourself? I work at a vets office and we have taught a few clients to do the injections to help save money. They can buy the entire bottle of medication from us at a discounted rate (we also had a client find it online, though we matched the price).
Pet insurance is a huge rip off. My friend used to work for one of the big name pet insurance companies and she told me to never even consider it. Their policies do not cover pre-existing conditions, breed specific conditions (ex Rotties are "prone" to hip problems, so even if your rotti got hit by a car and damamged his hip, it might not be covered because there might have been undiagnosed hip issues before the accident. Skeezy, huh?)
This is not true. My husband and I own a vet practice, and you would be surprised what insurance companies will pay for. Each one is different.
Sorry for the rant...