StuCool gives good advice; it's better to get a little experience in your welding class before you decide on a welder...

I have been welding for nearly 40 years and I agree that if money is no object you can't beat a Miller, but there are some nice machines out there that will do the job just as well. The challenge is finding them. For all around ease and convenience of use for the home shop, I recommend you take a look at the wire-feed welders that can do both MIG and flux core. (Flux core has spatter and slag that MIG doesn't; that's probably why tcodi says it sucks.) I have a Firepower FP130 welder that I bought from Welding Direct that came with the gauge and hoses to hook up for MIG. It also works with flux core wire and that is how I use it most of the time. It runs on 110 volt wall outlet and has a 40% duty cycle. It easily welds anything from body sheet metal to 1/4" plate. I also have an old Linde stick welder that I can use if I need to weld anything heavier than 1/4". Lowe's carries Lincoln welders and they have a small welder very similar to mine with a slightly lower duty cycle that you might want to look at.

As far as your project is concerned, a Model-A frame is very simple and you will have less labor involved if you just build a new frame from 2"x3" tubing. I have done several Model-A frames over the years and it's easier to replicate the frame from box tubing than to modify an original...