I recently bought a welder so I know the situation you're in. I also used to be employed as a welder in a former life but used big industrial stuff with a 425A BOC unit. I can arc no worries, but there's more to it than simply MIGS are easier and arcs are cheaper (btw they call it MMAW, FCAW various other confusing acronyms nowadays...).
With an arc /MMAW, you can get cheap inverter units that are insanely light and perform well. Some will do TIG (stainless only) but I'd stay clear of that unless you want to do it. The extra cost probably won't be worth it for the amount you'll use it. Arc also has the advantage of being able to get whatever rod you want to suit the material you're welding. It might save you once, but you'll be cheering when it does.
Gasless MIG / FCAW these days are fashionable. You don't need gas and they are simpler to weld. Reels cost a mint but you probably won't use much to care. IGNORE thickness measurements quoted - this is advice only and in reality you can weld whatever you want. Ask the salesman about duty cycles. This is much more important than the xxxA stamped on the side when it comes to quality. Also, as a rule of thumb - the heavier the better.
As Ducatistu said, you can get dedicated gasless units. This is probably suited for you, specifically in terms of price. My limited experience with 0.8 gasless wire though is it's **** and I can't wait to get a cylinder. Mind you I'm used to the best. Both my old $6k welder and a $400 gasless will join 8mm plate though, so the job still gets done.
My advice - get a gasless MIG that's the heaviest and most expensive you can afford. If you can weld, go an inverter arc until you want to commit to a 15A mig. Avoid Unimig, try to stick to Lincoln or Bossweld, or something US or European.
Or ignore all advice and get a cheap eBay job which will, in all honesty, probably do all you want it to. I like buying from my local welding store though so that when I need a tip or mask cover, there's more of a chance he'll be there.