I might misunderstand what you're talking about since I'm from central Europe, but here a metal garage is a much better choice by miles... And especially for a garage where I grind and weld stuff, I'd be very scared to even consider wood or flammable materials.
I'm also a bit on the cheap side, so I scouted for old materials. I know a guy who disassembles industrial garages and he offered me the "sandwich" aluminium panels. You can do a garage with those in no time. But I didn't like the foam inside (was still concerned about fires, though tbf maybe a bit excessive). Instead I bought the bare aluminium panels he had. They were from some old chicken farm, 4€/square meter - about half the cost of new steel roofing. I bought all the stock he had, took a week to pressure wash it and used stainless rivets in all the old holes. For the garage I planned on adding insulation, but I also used the roof for a car canopy and I glued on felt ("dripstop", a local company makes it and I bought it straight from them, 1€ per square meter of a faulty roll but half of it was useful, so I got through really cheaply). All together it took me two weeks to properly clean all the panels and apply that felt (otherwise condensation makes water drip off of it), but the panels were like new and industrial-thick (I think a bit over 1mm, pretty good for something like this, and with tall "waves").
This was about 7 years ago when steel was quite cheap compared to today. I ordered 180x50 rectangular tubing, 4mm thick. The odd size was so the tubes supported the outer and inner walls. They were used as pillars around the garage. When the concrete base was made, I also welded thick flat steel on the rebar, right where the pillars were supposed to go, so they're not moving... On the pillars, across the perimeter of the garage, I welded 40x20 3mm thick rectangular tubing on four levels on the outer side, so I could screw on the panels. On top, to connect the pillars, I had a bunch of old railroad tracks for very cheap and used those (basically very beefy I beams), and also added strong braces. This took about 4 days to get everything nice and level. On top of the I beams, I also welded on the 40x20mm rectangular tubing so I could attach the roof panels easily. It took me three days to clean the welds and paint everything properly.
Then the panels were on in a day. At first I struggled to get the screws right in the just 20mm wide tube, but then got the brilliant idea to search for it with a magnet! Didn't miss one screw afterwards.
Then I used non-flammable insulation (glass wool) and some fire-resistant plasterboards to cover it all up. The plasterboards are mounted directly to the 180x50 rectangular tubes. All panels and fibreboards were attached with self-cutting stainless steel screws, but turns out the stainless ones aren't that great for drilling and cutting thick steel so I used a normal drill first and then popped the screw in instead otherwise I had a bunch of issues. The tapered phillips head self cutting screws for the plasterboard were a bit tricky to find (had to order online).
To keep wiring simple and practical in the garage, I just ran a big PVC electrical channel on top of it all around it and pulled cables out of it, and all components are on top of plaster board...
On the end of the garage I also cut holes to the steel beams in the wall and welded on that thick 180x50 tubing straight out for a fixed table (also some bracing). It's amazing since I can use the broom under it easily since there are no table legs, but it's really rigid. On another pillar I did a similar stand just for a big vise, and on another I made a stand for a bench grinder.
I also left some holes in the top plasterboard and welded on some spacers and two thinner I profiles, so I can use them to winch stuff and even use them as rails if I'd make something that'd roll on them...
There aren't many things that could catch on fire inside, and the aluminium won't rust much anyway, so I think this garage will outlast me.
All together, it took me about two months to finish it all, and I didn't quite break the bank (steel was really cheap at the time, I think I gave 1500€ for it all, another ~100€ for the paint, some 500€ for the concrete, about 300-400€ for the fireproof plasterboard... We even poured the concrete base ourselves. I think I paid 1700€ for the aluminium panels, but had a bunch left over afterwards.
Welding profiles is quite easy, and if you place them together smart (ideally, the structure should stand without the welds if there's no wind...) it is not an issue. Of course it's very overbuilt, a structural engineer would use way less material, but I'd pay more for a structural engineer than if I just bought more material.