1. Get hands-on instruction. I've taught myself lots of things reading books, web surfing and trial and error. I currently have 3 welders and had a fourth. Many local trade school programs have a course for farmers, hobbyists, etc but I haven't connected yet. So I'm a hacker, barely getting by. This is one of those things where you want 'perfect practice' so you don't develop bad habits.
2. If I'm guessing your situation, I'd go with the mail order dual-voltage multi-function machine. I bought a Yeswelder a couple of years ago when it was the hot name. Now Arc Captain is hot, Amico was at one time. These are all solid state machines, not transformer. Mine will do wire, rod, and lift tig. It didn't come with a gas regulator or tig torch, which is fine since I don't anticipate doing MIG or TIG.
The first time I tried mine on 110 with flux-core wire, I was surprised at the power compared to my Craftsman transformer 110 flux machine. But if you're welding much over 1/8" material, you're likely to yearn for 220.
There are outfits available with regulator, tig torch and foot pedal. If you're thinking of doing TIG, I'd buy those upfront, in case the machine becomes obsolete. I wouldn't buy the plasma cut option. (That's not an informed rec., it just seems like a lot to ask of one machine. And $.)
I think I nearly duplicated
@NvRudder's post.
3. Have a good grinder and plenty of disks on hand.
Here's an example of what's out there. This one includes a spool gun, useful for wire welding aluminum.