My advice, having several different welding machines, I would look at buying a 110v MIG unit that can run gas. If you are just doing sheet metal work, you can buy a 110v MIG fairly cheap, along with a regulator and an argon mix tank. Flux MIG wire is good in a pinch, but also gives you lots of spatter and can leave some flux in the weld. I have one, and use it only when I have to.
TIG is wonderful, but is an expensive machine to purchase, still have to buy a bottle for gas. I have a tig unit that uses an stick welding machine for power. I have to say, I have a Miller 135, and find that it is my go to machine for most welding applications in the shop. Unless it is heavy steel welding, its small, portable, and easy. I do wish that I can justify buying a Miller 212 or 252, but haven't had a job come in yet that the 135 can't handle.
