Hi VM,
there seems to be a million tricky little welders in the market these days so it is hard to pick one. So many you see just laying down a weld that looks perfect. Personally most of the time I use my old arc welder I bought back in 64 and it has been in constant use ever since. I have a mig but I find that they are problematic with the wire feed so I don't bother with it unless I have to weld very thin metal. Then w\hat welder to get depends a lot on your experience. Arc is the cheapest to buy and then it depends on the quality of the rods you but. I buy the cheap Chinese rods but they are problematic starting an arc, but once started they weld fine. In summing it up I would get a small cheap arc welder, probably second hand Ozito or similar for $50 and practice practice then practice again. Big problem is you usually want to repair something that has broken and the reason it has broken is because it suffers vibration or strain and repairing this is never easy when you are learning to weld. As for the rods use either 2mm or 2.5mm don't try the 3.2's the welder won't handle them properly