what is the least expensive welder i can get away with ?

I have a Lincoln Weld PAC 135, paid about $400. I have had it for about 8 years and have never had an issue with it. I believe it has been replaced by the 140.

Whether you buy new, used check your local welding supply store and get what they sell. Makes life easier when you need parts or supplies. My neighbor has a Clark and no one has parts in stock and he is always borrowing mine.