Have you though about which welding process you are interested in?
Stick, Mig, Tig, Oxy/fuel. And to help answer that question, think about the type and thickness of the metals you intend to weld. Also think about how much money you want to invest up front. I have a nice DC stick rig, it was cheap to buy, and consumables are cheap and easy. It does most of what I need. But your needs may be different. There are plus and minus points to each process. Professional welders will likely have equipment for all of the processes and choose based upon the job at hand. Welding is a subject you could spend a long time becoming an expert welder, or it could be something you just play with on the weekend, It all depends on how much time, money and effort you want to put in to it.
James K0UA