Goodreads.com's Maimoninides pages have a bunch of Rambam's books on medicine(a dozen of them), as well as everything else. Just click on the titles of the ones you want, and then use the "Get a copy" links. One of them, his "Regimen on Health" treatise, is only available on Kindle, but the rest of them are available in print copies. One of his most famous works is his series of treatises collected and published as "Medical Aphorisms", which are his compilations of information from Galen and other ancient medical authorities, some lost except for Maimonides' extracts of them. Its five volumes are available, except for the last one which will be published next month. I don't know the size of the straw that will break your bank's back, but most of his works are less than $100US - the exceptions being long out-of-print items.