You're going to have to visit a doctor in order to get a prescription for your levo as very few doctors will write a script without seeing you, unless you are an established patient. You can, however, go to a walk-in clinic, where you will be charged according to your income, which is often very little.
It's important to note, that if you haven't had thyroid blood work in a while, that may also be required, as well, but the doctor you see may give you a script to tide you over until that can be done.
Prescriptions are written online unless you are already established with a doctor and they write the prescription via their patient portal.
There appear to be many (dozens?) of nurse practitioners working in your own area in or near Leesburg, FL (why try to get a renewal online?).
A visit to a medical clinic to get your regular prescription refilled ought not cost you $100's out of pocket, I'd of thought.