I might be able to help you a little, I am on my 4th or possibly 5th attempt to arrange my Garage Shop for functionality. I am working with a 2 car garage, and thankfully my home's breaker box is also located in the Garage. My projects range from small wood toys and such to building a off road buggy and home built airplane (soon I hope).
The biggest key to keeping a small space functional AND safe is to keep as much as possible stored out of the way. Since you are wanting to learn many processes, I recommend you build your own stuff incrementally, but be prepared to rebuild some things as you learn new skills.
My biggest suggest is to prioritize the skills you want to learn, and allow that priority list to drive the stuff you build for your shop. For example, I wanted to learn to weld with anything other than O/A as my first skill. I bought the MIG welder, and Plasma Cutter (I didn't want to spend all my time with a hacksaw). I used these to build my second work bench (first was wood). Welds were crappy, top was warped, and I was afraid to put anything more than 50lbs on it, but it was serviceable for me to stand and weld scrap together until I got better. Then I built a more solid and mostly square bench and the old one become more scrap to practice on.
For me I quickly dumped MIG in favor of TIG, so I bought my TIG setup, and went back to scrap welding, eventually I rebuilt my bench again, this time I built it as a down draft table to double as a Plasma cutting table. As I got better at welding it become time to build something other that a welding table... CRAP, my current table didn't have much to clamp to, it had 1" bar stock running across for cutting.. Guess it's time to build yet another table... This worked great for me... sort of... I finally built a few other things I needed like a materials cart, a few cabinets etc...
I finally THOUGHT I was getting closer to building my plane (yes it requires another bench, this time 16')... Yet another bench completed, and yup you guessed it, it was a 16' single bench... I started practicing on Chrome Molly Round tube with various angles and joints. Learned I needed more practice before I build something that I am going to fly. In doing research I come across a home built airplane page that talked about building your work bench modular in smaller more easily handled pieces, and by this point I was already frustrated with the single 16' bench with other benches for cutting and welding, so yup you guessed it, time for another bench, but this time I'm gonna torcher myself by building a bunch of smaller benches!!!
Essentially this is where I am at now. I have taken on the project of building a mini dune buggy so that I can better improve my overall fabrication skills before tasking the airplane. A dune buggy uses nearly the same construction processes as the airplane, same types of joints, round and square tubing etc... And best of all if something breaks I won't go tumbling thousands of feet all the while watching as the Sudden stop at the bottom of that journey quickly approaches.
The buggy has a number of things that need to be CNC Cut for it, and me being me, and the fact that I have become an expert bench builder (or so it feels), I've gotten distracted by all the talk of building your own CNC Plasma/Router table. I look over all the things I have built so far, and I look over the requirements for the CNC stuff, and I keep asking myself, why should I pay a few hundred dollars for someone else to cut these pieces when I could take the same money and build my own CNC table.... Oooops... another dang bench
You mention wanting to keep the cost down (best of luck there). I bought my Lincoln MIG welder from Home Depot ($399) (big mistake), my Plasma cutter is a cheap Amazon buy ($400), and so far has held up well. My TIG is another Amazon Buy ($900 Machine only), Argon bottles and regulators locally (est. $500). Mill was a craigslist buy for $700 and Lathe was another CL buy for $1500. And the list goes on and on and on... Not to mention the replacement of cheap tools with more expensive better tools.
Add to that that I am incrementally learning different skills with the end goal being to build the airplane. My starting point was a small toolbox with basic hand tools, and your basic set of electric and cordless tools. My skillset was basic/medium woodworking, and general farm jack of all trades.
Here is where I am right now on my shop setup:
Down the center of my Garage I have my workbench which is a total of 16' long, and does triple/quadruple duty as a welding/cutting/assembly table, as well it functions as a wood feed bench for my Table Saw and wood working. I made several mistakes on my work bench, and have rebuilt it probably 5 or 6 times. What I have now is a modular bench that is comprised of multiple benches that are attached to each other. My table saw is 4x4', and with the blade fully down and removing the guides and such it does double duty for assembly. Next I have 6 benches that are 4'x2' which are currently supporting a 12' steel 7/16" plate. Soon this plate will be cut down for the benches. I will also be removing 2 of the benches to replace them with a single 4x4 downdraft cutting table which will eventually become a CNC table. When I get the cutting table finished I will have dual tops for it, one which is a flat working area with holes to double as a down draft sanding table, and then for the cutting I simply remove that top.
This modular bench setup allows for me to add/remove lengths easily, and having the various benches being 4x2 allows for fairly easy moving and storage of them. I would HIGHLY recommend this type of bench setup for tight spaces. You might even go so far as to make the legs removable for easier storage.
Over the workbench I have retractable Electricity, Air, and Oxy/Ace. My compressors and bottles are off to the side of the Garage in cabinets.
For welding, I am still using a cheap welding cart from Harbor Freight, with my TIG Welder, and for my Plasma Torch. I have a cheap Lincoln Wire Feed MIG welder that is on a shelf under the bench. I don't use it much so I haven't really done much with it.
Over the workbench I have a 1ton Gantry Crane (another Harbor Freight Tool), which I use to help me manhandle large and heavy stuff, even helps to unload from the truck. I supplement this with a 2 ton engine hoist that's folded up in a corner unless needed.
Something I would LIKE to do, but not sure how well it will work for me is to move my TIG welder and Plasma Cutter into the cabinet with my oxy/ace bottles, and then run the torch and petal to allow for a ceiling drop for them too. For most of my work I already drape the torch hose over the Gantry Crane to allow me to move around the table a little easier.
That describes the primary work area... This setup is still evolving, but I am getting closer and closer to "my" perfect work area...
I also built a small rolling materials storage cart, and for now it sits outside the Garage door where it irritates my neighbors.
For the rest of my tools, I have 2 small rolling tables, one has my Compound Miter Saw bolted down and has swinging wings off it to allow for more area to support work. The other table is simply 3x3, with a hard ply top, and this is used for all my other bench top tools.
Along one side wall I have my Mill and Lathe which are far too heavy to move around. I also have my Drill Press on a 3x3 wooden platform to stabilize it, and allow me to move it if needed. Eventually I will move things around here to allow me to put my band saw on this wall too, but for now its against the other wall.
I put my dust collector in the Attic over the Garage, and run the lines to the permanent placed tools, but for now the bench and other moving tools are stuck with a shopvac for dust collection...
The other wall is mostly cabinets.
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I made several mistakes in setting up that worked against me big time, the two biggest mistakes I made was to build my work bench as one long 16' bench, and I naively thought that putting wheels on it would allow me to roll it out of the way... The second biggest mistake was to try to make small rolling tables that were dedicated to my bench tools like planers, sanders, grinder etc... With the combination of the 16' bench and half a dozen small carts my Garage become a giant puzzle where I had to constantly move things around to get to the tools I needed.