New to the obsession, I mean game.

What are some good farming places for rares and formulas in Act 1? I've heard the centaur and the giant but they only spit out one thing and then nothing else. I exit back to the main screen and reenter each time.

Am I doing something wrong?

Welcome to the game.

You have been looking in the chests that both Nessus and the Cyclops have aren't you? Thing it they are pretty early in Act 1 so probably not the best places for rares.

I wouldn't bother farming this early, just keep playing through the game and pray to the RNG god to be kind to you.