Oestrogens. Generally 17β-estradiol. Oral or transdermal. Some countries also have injectables. I'm personally against injectables, but that's irrelevant.
Generic anti-androgens. Depending on the country, spironolactone (e.g. US) or cyproterone (e.g. Canada).
Those two are very often included in treatment. Some only prescribe oestrogens, but I personally think that's a bad approach. Of course, once testes are removed (orchiectomy or SRS) there's absolutely no need for an anti-androgen.
Occasionally, the following are added:
Dihydrotestosterone antagonists. Generally finasteride or dutasteride. Sometimes useful in halting male pattern baldness, as well as reducing body hair.
Progestogens. Generally medroxyprogesterone or micronised progesterone. Its effects on transsexuals are debated and unproven. Some believe it helps with breast growth. Others think it just acts as an androgen. Whichever the case, if they should be tried, that shouldn't be until a good year of HRT, according to some.
Insurance coverage: It varies. A lot of public programs cover HRT; others don't. For countries without public insurance like the US, it varies a lot. I've heard of some insurance companies covering it; of some not covering it. Some even cover SRS. You'll have to get information about yours.
Edit: Gosh, I was beaten to it. Twice.