It's hard to say exactly what may be available. 1. A lot of it depends on what what insurance you get. 2. A lot depends on what state you live in. 3. Hardly anyone understands what Obamacare actually does.
There are no epilepsy specific programs.
However...
While there is no "guarantee" of medical treatment in the US, that does NOT mean that you will go without. If you really need it, you will get it. The appearance is that American physicians and hospitals are heartless capitalists. The reality is that there is an immense amount of charity care being given.
In spite of it's faults the US healthcare system is one of the best, if not the best in the world. (That's not just my arrogant American jingoism speaking, it's true.) For the most part access to care is good here (although less so with Obamacare). It varies a lot from place to place, but you can often get an appointment with a GP in a week, and sometimes the same day. You can go to "urgent care" many places and be seen on a walk-in basis. Getting to an epileptologist or neurologist will take longer, but you can be seen by almost anyone you want, anywhere, if you are paying out of pocket (which doesn't necessarily mean full-price). Even with limited insurance you still have a lot of options.
If you are working full time, with Obamacare you should be able to get insurance of some sort. Depending on the "deductible" (the amount you have to spend before insurance kicks in) this may or may not be much help. "High deductible" insurance, like you will get from a lot of employers, is intended for healthy people who might get in a car wreck or something, not for people with chronic illnesses. Insurance may, or may not, pay for meds before you have reached the deductible. If it does, like other services it pays for, you may have a small "co-pay" (like the $12.00, you mentioned.)
For someone with epilepsy, it is best to have really good insurance that covers everything, or no insurance at all. Anywhere in the middle you have problems. Having average insurance, high deductible, or limited "HMO" insurance is often more expensive than having none. Those things are designed for healthy people who don't use a lot of medical care. Because people with epilepsy use a lot of healthcare, even if it's mostly just meds, you end up having to pay for most of your healthcare AND insurance. Good insurance, even if it is expensive, pays for all of it. It's cheaper to pay a lot for good insurance that covers what you need, than paying less for insurance that doesn't cover anything.
When you have no insurance you can get discounts and free meds.
If you don't have insurance doctors will give you a discount on services, but you have to ask, and tell them you don't have insurance. (The dirty secret is that the physicians theoretically charge price "A". The insurance company or medicare actually pays less than that, price "B". Price "B" may only be a fraction of "A". Unfortunately, when they charge you as a self-pay you are initially charged "A". If you ask, they will charge you price "C", which is significantly less than "A". The reality is that NO ONE knows what ANYTHING actually costs. It's stupid, but that's the way it works.)
If you don't have insurance most drug companies run "patient assistance programs", where you can get your meds free or at a discount, depending on the program and how much you earn. You have to fill out a sheet, have the doctor sign, and send it in. It's a pain, but invaluable. Drug companies have sent me $500-$700 worth of meds each month, totally free.
Whether you have insurance or not, the hospital will work with you if you can't pay your bill. When you get the bill (typically months after service), you have to call them. Most will give you a virtually unlimited time to make small payments toward the balance. Depending on circumstances they may forgive part or all of the bill.
You can also tell your doctor that you don't have the cash for certain services or medications if they aren't absolutely necessary. You can save hundreds on blood tests this way.
Generic medications are cheaper than brand-name. Sometimes they cost virtually nothing, other times they can still be pretty expensive. Older medications are also less expensive.
It may all sound very convoluted and nonsensical. It may be stupid, but that's the way it works. There have been times when I haven't been able to get some things I needed. For most of my life I had no insurance at all. On the other hand, I have also been to some of the best hospitals in the US. I'm not saying its the best arrangement, but for the most part it works. I have always been able to see a doctor, get my meds, and go to the emergency room.
I don't know how being a UK citizen might affect all that, but I'm sure there are expat websites with that info.
