Getting back to basics…what machines do you have? Getting a complete set should be a priority (you can skip the centraforge for a while, that’s high end stuff). You can craft them yourself or you can buy them. many stores (like High Ridge Market on Storis cough) have them for pretty cheap. If they are over 200 a part, skip it. you can find MUCH better deals…remember you need four of each for a whole machine.
There is money to be gained from breaking rocks. Not much, but you can gather a few smart stacks pretty easily and, with a bit a searching, you can find places to buy those rocks for 1 or 2 coin each. Also watch the “buying” baskets for things you can gather easily.