Well, if I offended you, don't think you are somehow in a small group of people. I offend a LOT of people.
That being said.
First question I would ask on this, why do you need to bury the cable to begin with? Is there a law that says it can't be done with areal cable?
Poles are reasonably cheap if needed and you could run areal wire out to the building and eliminate the trench and rigid pipe path.
Now for a bit of reason to do as much as you can instead of going with a minimum.
Say you feed it with the 3 runs of 12/2 that someone suggested. And then a killer deal on a larger lathe that needs 30 amps to run falls in your lap. 12 gauge wire is good for 20 amps not 30.
Point here is finding machines on the used market is sort of funny when you are on a budget. First the little table top 110 units are there. The Central Machinery stuff from harbor freight and similar low buck low quality gear. Then you get into the mid sized gear that people want new prices for (at least in my area of central Ohio and you aint far enough away that Ohioians aren't buying there) and it's 40 years old or better. But that's what everyone wants so they will pay the premium. Then you get into the bigger industrial gear that is heavy and hard to move and the price goes back down. But that stuff uses bigger motors and requires more power. But it's cheap to buy. Dragging something home to find out it can't be used sucks alot more than not having it at all. Trust me. I too know about being broke. Watching stuff rust away that I didn't have the money to invest in at the time and it sat and was ruined.
As far as how to do it on a shoestring.
First it doesn't ever happen overnight. It takes time to put together everything you need to do a project. Electrical systems don't come in a box that you buy and assemble. And that's actually a good thing, because you can buy your wire this week or month or whatever and maybe get some 4 square boxes to put outlets in and then next week get the outlets and faceplates. Once you have that stuff then it's the panel. and then later the breakers. do it slowly and it will come together.
The other thing to do is check the scrap yards for rolls of wire and long sections of cut wire.
As long as it's long enough and the correct gauge then it will work. Color isn't important. If it's all orange, so be it. You grab a roll of white, black, red and green tape and mark your conductors.
So don't be offended,,, be motivated to figure it out. Or be offended and let that motivate you. Yes, family comes before all else. Don't assume I don't know about that either.