I'm low on money and need to start mining as cheaply as possible. I have my current gaming pc mining $100/month and am looking to buy a new pc for mining only. I need to know the best low cost gpu to start with and would love to possibly eventually make a living mining ethereum. I'm looking to start off with 1 gpu but eventually turn it into 2-3 gpu's for this pc until I can afford a motherboard capable of holding 5 gpu's for 2-3 gpu's do I need a quad core amd processor? or will a cheap $40 dual core work as well? I need the build as cost effective as possible and will borrow ram and an hdd from my current pc.