If your going to spend good money for one, try and buy a Miller, Lincoln, or Hobart. Are you thinking MIG welder? 110V or 220V model.
Any of these three have a very excellent reputation, parts availability, and customer support. Do some homework and comparison shopping at your local welding supply, they should be more than willing to help you buy the right unit for your needs, and get you setup right. All depends on what your plans are for it.
I would try and stay away from the off-brands for numerous reasons, some of which I mentioned above.
I am going to get a 110v MIG. I have body work I am going to be doing so I want a good welder that will lay down some good flat beads but I don't want to spend a ton on one either. But I guess when you buy one you bought it for life.
You are better off spending slightly more to get a quality welder then saving and getting an "off brand". Service, parts, availible, etc.. Duty cycle usually suffers also. Stick with the main brands- you'll be glad you did in the end...
I had a Century 120 volt 110 amp mig and it was and still is a decent welder. Gave it to my son in law when I got the Lincoln 175 220 volt machine I have now. Easy to get repair items and normal wear parts for something with a name brand. Buy the cheap o machines and you can not get parts to use them when things wear out. JMHO, RM
Miller's are great, but don't discount the Hobart which is made by Miller. I have the Handler 180 and it is a great 230 volt machine. They are a little bit cheaper (try Tractor Supply) but fit the bill quite nicely. They have a 110 machine too (HH 140).