I don't have any of my receipts and I didn't keep track of what I spent on my build, but here are some thoughts on costs.
I didn't have tools, so I had to buy a jigsaw, impact driver, and Rockwell hand saw (that's really for trim, to barely cuts 2x4s.) I had small household tools, tape measures, lumber pencils. Then there's the adhesives, lots of wood glue. Then there's fasteners, omg, you won't believe how much you will learn about wood screws, self tapping this, die cut that, ect. When I see guys who have drawers and drawers full of screws, nuts, and bolts now, I think "yeah I get it."
After I had the basics in power tools, adhesives, and fasteners, there was the costs of raw materials. Just making a bed, it's about $200 if you have everything. About $300-$400 if you need fasteners, wood glue. I'm not talking mahogany, that's just cedar at Lowes.
More about raw materials, there's the 3/4 plywood for a floor, Relectix, polyiso for the walls ( I spent a little over $100 on my polyiso.) Then the thin plywood over the walls and ceiling. Then there's the flooring. Then the fan.
Then, here's where things add up. It's the do-overs, fixing mistakes, endless runs to HD or Lowes. Beware of inside vs outside measurements. My bed was 63 inches long, so my center support beam needed to be 3 inches less, to take into the account the 1.5 inches of the two sides. Well, I cut the piece too short and I made that same mistake THREE TIMES! Beware of inside vs outside measurements!
Then there's the "setting up house part." The storage bins that work best, over the wall storage, rugs, magnets, hooks, bric-a-brac, this, that, that can be endless.
This is just me, I'm a low-skilled do it yourselfer doing basic carpentry. I'm going to make more mistakes than someone who works construction and can judge how much material is needed without too much overage, what kind of this or that is better, cutting down on trips to the store, returns. When I can make an RTR, I'll show off my "leaning Tower of Pisa" cedar chest. The whole thing is crooked.
Well, I don't know how much I spent, but it's in the multiple thousands, I'm sure of that. My power is supplied by a Goal Zero Yeti, and a small solar panel, there's another thousand almost. No refrigerator, so my Yeti cooler is another $400, but I've had that for awhile now. With my new re-org, I finally feel like I'm "done," I don't have any other projects planned for it.