Hey Mike, You already have a Big-40. as a power supply to start with. If you just want to play and experiment with a low budget you could use a Argon Cooled torch and scratch start using your Big 40. The gas cooled torch has Amperage limitations, BE AWARE of those and set your machine accordingly. I have used Miller equipment extensively and will not apologize for that fact. I have also used Hobart, Lincoln, Linde, ESAB and many others that I cant recall at this time. If You are going to spend the money I would buy a Miller Dynasty. There is also a related thread that was started by Steve St. Laurent in shop forum, where many folks chimed in to help him get started in TIG welding. He chose to purchase a different power supply because of the cost. He deserves a " You Done Good Pilgrim" for his efforts. A very good read. You will need an Argon Bottle , flow meter, Torch, Gas lens collet body, collets, cups and tungsten. An air (argon) cooled torch has the gas on/off valve on the handle. Hope this helps. GregH