The first thing, that I would do is to. as you said, is to speak to a psychiatrist who will work on less expensive generic medications. Further, many brand makers have programs for those who cannot afford the brand medicine, but cannot afford to pay a reduced fee. Certain pharmacies like Walgreen and CVS also have programs for the medically indigent. Have no shame, the brand companies make a a fortune-any break you can get is justified.
I do not mean to ignore your question, but the best source for the medications you seek would be be an appropriate psycolopharmoclogist. as well as the pharmacist. I am sorry I cannot give exact equivalents. My hope is that this is more useful and gets you closer to the information you seek.