If you want to go cheap with a tig welder any and I mean any, DC buzz box will do the job as a power source. I've got a Lincoln Ideal arc 250 300 Ac Dc machine I use. I bought a manual tig torch (for touch start) with a valve on the torch for turning on the shielding gas, took a bolt and nut tightened them up on the tig torch cable and connected into my stick whip. Set the machine up for straight polarity and away I go.
It works great, thats how we weld out in the field on pipe. No foot pedal, no high freq start, touch and go.
Of course your limited to steel and its alloys but if your not going to do anything on aluminum or magnesium your set.
My machine has a min amp of 30 and to do finer work a rheostat of some sort would help on the thinner materials. I was told running a lead off my ground to a flat bar made of copper and using another lead that slid from one end of the copper flat bar to the other would give me the resistance I wanted. Going to try it one of these days, sounds like it might work.
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