>>1750
the writings of epictetus (the enchiridion first), marcus aurelius, socrates, plato( the republic in particular, since pretty much anything else you read is going to reference it heavily), Aristotle, in that order.
i recommend this order because stoicisim is pretty easy to understand, and pretty much everyone else is going to reference the works of plato, aristotle, and socrates so it would be good to read their works first so you understand what theyre talking about.
also you can read all of their works online for free http://classics.mit.edu/Browse/index-Epictetus.html
theres also audiobooks available for these for free, either through youtube or librevox, but most are librevox and librevox has no standards for recording so good luck finding one thats you can stand to listen to. i will say that the apology of socrates is actually decent though.