WELCOME TO THE AWS WELDING FORUM!!
You have sure started out with a bang. There are many cheap welders available. Many would do a job standard for what they cost... zero in...zero out.
It is at least as true in welders as in almost everything available for public purchase, you get what you pay for.
Even most of the cheapest welders that will even come close to doing what you would want are going to run over $500.
Just my two tin pennies worth. Maybe some here with more experience with the cheaper units will chime in with more encouraging words.
He Is In Control, Have a Great Day, Brent
I'll chime in. You can buy something of quality for $300 and it will do everything you mention. You just have to buy used. Hey, it's like buying a used car, buyer beware. Look for the deal, and remember to test drive before you buy.
Downsizers, divorce and rent money. That and everyone thinks they can weld but most give up long before they get educated and reasonably good in the skills department, they get frustrated then after it collects some dust...they sell.
He's your deal.
You won't likely get a gas cylinder and flow meter, but $300 should buy you 130 amps minimum, 20amp/120volt supply for portability, likely 20% Duty cycle, and while running a gasless wire should have a built in gas package. That will weld 1/4" which is with in the rating of most machines and what you want to do. It won't be nose down ass up but it will weld some serious material given the time.
Millermatic 130, Hobart Handler 130, Lincoln 130. Hobart has a bit of lesser rep so they are the best deal.
I'm not saying off shore manufactured "NEW" should be ruled out however. What you need to do is learn enough about welding to understand some basic welding knowledge, compare consumable costs and availability for those consumables. Compare the materials used in construction and you'll notice plastic where aluminum might be, a bushing where a bearing might be used, cheap switches plugs and don't forget service issues.
Red White and Blue.
As far as cheap SMAW equipment, an AC transformer is the bomb. But unless it's a 220v machine, you will be buying a 120V inverter power source for that money. Or 120v ac transformer welding with a 5/64" electrode lol. Buy new. Pay with Visa and double your warrenty. Remember when your VCR crapped out you didn't get it fixed if it was off warrenty.
As for your future spending... Don't buy what you won't use.
My 2 cents worth.
I'll just put it simply. Cheap equals junk.
I was in your same situation 17 years ago. I had a 220 outlet in my carport after I unplugged my dryer. I bought a Miller Thunderbolt stick welder for right around $400. It would weld projects similar to yours no problem. The thing about my Miller is this. Your $100 Harbor Freight welder vs my Miller after 17 years, I can go to the shop, turn it on right now and weld all day long with it. I doubt the $100 joloppy will make it that long.
The hobarts from Tractor Supply are nice. I've got a 110 that has welded 100's of feet of handrail and aluminum(light with my special trick). A larger 220 machine is not outrageous in cost. The harbor freight welders and things like that I'd stay the heck away from them unless you just like throwing away money. Honestly, save your $300 and add to it. They're not going to stop making welding machines next week so you still have time to put away another couple hundred bucks to get what you want and not settle for something less than what you want now.