You will probably want to use a least one good overclockable ATI / AMD graphics card. You will need a sufficient power supply for it. It will take months to earn enough to pay for the graphics card, but DOGE is probably the most profitable widely established coin to mine.
The processing power of the card is called the hashrate.
This website will let you figure out what hashrate you might get for each graphics card. (The website isn't for DOGE, but DOGE uses the same algorithm, so the numbers are the same.)
This website lets you see how profitable some coins, including DOGE, would be at whatever hashrate your card generates. From that, you can play with various scenarios.
But really, you need to be educating yourself more. Go to the DOGE reddit website, look for the links about education and just start reading.