Scavenging for junk and bottle caps is part of Fallout 4's charm, but that doesn't change the fact that the in-game currency is scarce and that rewarded missions don't yield much of it. Just like the real world, money can solve many of your problems, so here's a glitch you can exploit for infinite caps.
What You'll Need
Before you begin executing the exploit, you need to make sure that you have enough bottle caps to begin with. The amount will depend on the kind of item you'll use for the glitch. The more expensive it is, the faster you can reach your goal amount.
You will also need the rank two Local Leader perk under Charisma because the exploit will require you to build stores. It can only be unlocked when your Charisma is at level six, so you might want to do a few side missions to level up first.
The most expensive store you can get is the Armor Emporium or Weapon Emporium. Both cost you 3,000 bottle caps, three Steel, and five Wood. However, you will need to unlock the rank two Cap Collector perk under Charisma for the emporium. Don't worry, any store will do.
Steps for the Exploit
Once you have done everything you need, go ahead and build the store of your choice and set it down, preferably in a place where settlers won't roam in or other items might be selected by accident. After that, be ready to press keys or buttons quickly.
Now that the item is placed, you will want to press the button for Scrap and then almost simultaneously follow it by pressing the Store button and hold. This would be easier with a controller since the buttons are close to each other.
You know that you've done it correctly if the Scrap menu is overlapping the Store menu, as shown in the photo above. Keep holding the Store button as you press the prompt for scrapping the item and then storing it.
You can repeat this several times and then finally collect the bottle caps you've accumulated through the Workshop inventory, just be careful since some players say that the exploit doesn't work when you exceed 100,000 bottle caps. Just check from time to time to be sure.
Now You Can Have Unlimited Junk and Resources
Once you collect enough bottle caps from the exploit, you won't really have to collect junk items from the places you go to. You can just purchase them from Merchants. The base resources like Wood and Steel are sold by shipment in certain merchants, which goes the same for other items.
With this, you won't have to risk being over-encumbered, which seems to be a problem for all the hoarders out there, which is basically every player since it's required by the game. Maybe collect rare items like Military Circuit Boards and such so you won't have to go to several Merchants to find them.