If you can't pay for a medical treatment, are there options besides credit/payment plans? (New Orleans area)
I apologize if this doesn't answer your question or you've already explored it, but "payment plan" can turn that $700 cost into a something a lot more manageable - I am pretty sure most providers will work with you (often without interest) to come up with something you can afford.
My wife and I had a slew of medical bills last year and one of them slipped past me and ended up in a collection agency. They offered me a few different payment plans without interest - we have good credit so that was part of it I'm sure, but I would shop around and talk to the providers billing departments on what they can do.
Sorry I don't have anything more helpful.