Re: Mestinon,
With a prescription you could order from Canada, they are usually cheaper. Also it's cheaper when you buy more at once, plus that way you are paying for shipping only every 2 or 3 months. One example of a site is northdrugstore.com/buy-Mestinon.html though I have no familiarity with them, they just came up in google.
But it's probably best to have a job that has decent coverage