...video of a storage container build... how much... middle of the night and you need the last nut or bolt that you dont have anymore...
Better question is how much did it cost to make that storage contraption. That thing probably cost more than the cost of the fasteners.
That thing you NEED at 2am rarely happens but when it does, I usually solve that problem with taps and dies. Even if it's just temporary, you can always make something.
Consumable fasteners like drywall screws, wood screws or nails are hardware store or big-box purchases. Not usually worth the time to call in a favor. For the rest of it, I have a small parts washer and tumbler. Clean them up, measure to make sure they are in spec then send them out to be re-plated. They come back like NOS or OEM fasteners. Most of my car stuff is organized by BMW factory part numbers, not fastener size/pitch.
You can do it on the cheap if you dump degreaser into a 5-gal bucket full of fasteners, then rinse, dry, inspect (bad or cammed out threads or heads), tumble (tumblers are pretty cheap) then send out for plating. If you do some decent volume you can scrap the junk.
Kept all of the bolts from disassembled/parted out engines and frames over the years if they were of good quality and undamaged... added up to rather a lot over time. Most others bought from fastener shops, they’re really quite inexpensive compared to buying from the big name hardware stores around here.
I did some very bad things back in the day. Me and a buddy went through a lot of sawzall blades. Back before cash for clunkers, cars were stupid cheap. You could buy a $300-$500 car, part it then scrap it back for $250-$300.
Some Lincoln Continentals came with a BMW forged crank, BMW e21's came with Recaros, 5spd, limited slip, driveshaft, steering wheel, etc. Range Rovers and Buicks had the V8 he needed for his TR8. We amassed a ****-ton of stuff. It also checked the metric and standard "automotive fastener" checkbox.
We also have a really good mom & pop hardware store about 10 minutes down the road. The kind where they don't wear aprons or uniforms to work, there's usually 1-2 dogs roaming around and they have a popcorn machine for customers. (and the grandson owns/runs the store today) If I pay retail I go there but usually I know people who know people who can find stuff that fell off the back of a truck.
Genuine Aircraft Hardware, Aircraft Spruce or Luky's.
Aircraft Spruce has always been decent on price. Some older BMW ball joint cups (steering pitman arm meets base of strut tube) need either six $10++ bolts from the stealership or Aircraft Spruce sells really nice stuff with safety wire holes pre-drilled in the bolt heads. Makes you look like a pro at tech vs. DIY with drill press.