I can recommend a good little welder, if you'd doing parts that are non-critical, and you can only do stick. One might still find one used, such as on eBay, etc.
I had a small welder, made by Sears, and it couldn't be but a 30 amp welder, that ran on 115 Vac. It was about the size of a bench battery charger. The largest rod you could use, was probably 3/32. I used to use 1/16" rods, and lay small spots of weld to build up firing pins on the old Iver Johnson, etc, revolver hammers. You do it by adding one little round glob of metal at a time, like your doing a tack weld, until you get enough that you can shape, harden, then temper it.
However, now, you can get a small combo DC TIG-Stick welder, from Harbor Freight, pretty cheap, that will work, as you only need low amounts of current on gun work anyhow. Use a foot pedal with it, (what I prefer), and you can do wonders with one. They have one with a high freq. starter on it, below. All you would need is gas and wire/rod.
http://www.harborfreight.com/240-volt-inverter-arctig-welder-with-digital-readout-62486.html