Water and drugs rule.

Selling Mentats to the fiends. Gotta turn a profit somehow.

I have level 3, bars and clinics in every settlement, which so far is the only use I've found for caps.

Well, you can spend them on shipments. Other than that, the gear you can create is usually better than what the vendors sell.

I buy shipments which seem useful to me, but steel, wood and some others just seem a waste.

I could ofc go crazy and build stuff just for xp but I lose fun in that super fast, I rather explore and quest.

As to weapons and armour I have what I need as base types go and those are fully modded, so to get better I need legendary drops...

There might be some legendary items at vendors so far I haven't found anything interesting for me. (unarmed with deathclaw gauntlet, ballistic weave clothes and combat armour)

Both of my playthroughs have ended with about 50K net worth in just caps, not counting the arsenals and closets full of power armor. Management of your resources is key to making sure the end game portion is something you can make it through. The final fight as an Institute player, for instance, is freaking brutal. Anything less than the absolute best gear and you're not getting through it.

If you need early caps, here's a few things to do, starting as early as you can:

1. Build multiple water purifiers (industrial size if you can), in one settlement. Get water production near 200ish. Every couple days clear the Purified Water out of the Workbench (usually 100+) and schlep it into a settlement with vendors (or Diamond City or Goodneighbor) and trade it for what you need. Ammo, stimpaks, et al.

2. It's an investment, but get vendors up in your own settlements as soon as you can. Over time, you will make far more caps than you invested. Just pull it off the workbench every few days.

3. Sell any ammo you aren't using that type of. Not using pistols? Sell all your .44 and 10mm ammo. Not using heavy weapons? Sell all your 5mm, Flamer Fuel, Missiles, and even MiniNukes. The ammo I find that can't really be parted with is Fusion Cells, .45acp, .308, and .50 cal and 2mm EC.

4. Pick up any and every Aid item you find. That stuff has the best weight/value ratio you can find typically (.5 or .1 per item). Sell it if you can't or won't use it. Don't keep spare Stimpaks once you're past mid-game, as you usually can't burn through them fast enough. I keep 25ish on my character(s) at any one time. Any spares picked up I sell. Same with RadAway and Rad-X. Early on, though, especially on Survival, you'll want to hoard these -- but they become a gold mine later.

5. Don't chunk it, junk it. The very first perk you spend in the game should be Scrapper 1. There are a wealth of weapon and armor workstations throughout the world, often in raider camps and Red Rockets. After each fight, if near one, gather all the weapons and armor you can from the fallen and deconstruct it into useful materials. You're especially looking for guns with suppressors and scopes, as those break apart into the rarest components (aluminum, nuclear material, copper, crystal, etc). This saves you weight (as components are light) and saves you time/resources of acquiring those rare materials later. Rule of thumb - the longer the name of a piece of random equipment, the better it junks for.

6. Use the Component highlight feature of your PipBoy extensively. You can sort your inventory by component under the Junk tab. There you can manually select what you want to tag (not just what you're out of). Make sure to tag and collect the following: Aluminum, Nuclear Material, Ceramic, Circuitry, Fiber Optics, Copper, Oil, Ballistic Fiber, and most importantly - Adhesive.

7. Make every transaction with a vendor a positive one. Never be in the red if you can avoid it (except for key purchases like Overseer's Guardian or Big Boy). Even if it's just +1 cap or whatever. Trade away the ammo you don't need, the stimpaks, et al. This lets the caps reserve you maintain be there for emergencies, purchasing needed Legendaries, building your own vendors (or investing in them), bribing your way through NPC encounters, and so on. I see caps as a way of measuring worth, instead of as a currency. 'Ok, this pile of purified water and these 250 .38 special bullets are worth X amount of caps -- which will net me Y amount of stuff I need...'

8. More Long Term - Upgrade and maintain your settlements. This is, ultimately, what gives you the resources you need. Multiple settlements all producing foodstuffs (to make adhesives with), purified water (to trade for ammo), and salvage (to junk for crafting materials) will add up. If you have almost every settlement unlocked and running efficiently, you will not want for anything. It does require time and in game material investments to get off the ground though. It'll seem like a huge waste... until suddenly the only mats you ever need to gather again are rare ones like Nuclear Material and Fiber Optics.

As long as you don't hoard everything you pick up, you should be perfectly fine. Pretty much all of the 8 points above are excellent advice. I have to ask the OP though, what are you doing with all of the stuff you loot?

https://youtu.be/FJpwJqxaCEc boom fastest money glitch

Fact is, you don't need that much money. Actually, you never did in any Fallout game. Some pieces may be worth purchasing, but in general, the armor you loot with a few homemade buffs is sufficient. As are the weapons.

I also don't sell my ammo for weapons I don't use. I hand them to the settlers. You autolose if you're not there for an attack, but if you're there and you have well equipped homies, it can make a difference.

Drugs and purified water are easy to come by and I'm swimming in caps, just selling that.

I'm on xbox one, so console commands are out (so far as I'm aware). Maybe I am doing something wrong, but no vendor I have ever run into has had more than 600 caps, so making the money I am after by selling them water would be quite time consuming.

If there is a way to increase the vendors caps available into the thousands (is there?) than sure I would just sell water, but that doesn't seem to be the case for me.

The big question remains - why do you even need money? Selling water is for trading in items you can use for settlement building or for equipping companions or settlers.

There's no need for money in this game. I have to deal with the same limits and have 50 k worth of caps. So believe me, it works. It just doesn't work like the fairy waving her magic wand.

ditto..

only need to Trade to get what you want.

house in DC and paying ransoms are only need for caps so far for me.

If you max out the Local Leader and Cap Collector perks you can establish vendors at your settlements and invest an additional 500 caps with your own vendors and any other vendor in the game to increase their baseline number of caps. This is a very worthwhile investment. All of my vendors at Sanctuary, Trashcan Carla, the vendors in Goodneighbor and Diamond City, and a few other scattered vendors carry a baseline of about 1300-1400 caps after making this initial investment in each of them. It has paid itself back several times over already.

Addtionally, make sure that you have your charisma as high as you can get it while buying/selling by wearing a charisma boosting outfit and popping some graqe mentats if you're so inclined. You get the best possible buying/selling prices at 16 charisma.

If this seems too involving to you, you can use the Dogmeat item duplication trick and keep duplicating the Fatman or something like that. But honestly I feel like this is more work than just producing water. Dogmeat is a pain in the ass and getting the timing just right is kind of difficult at first. I've only ever done it once just because I was curious to see how it worked. Vendors only carry so many caps at once. You aren't going to make caps any faster by having a smaller number of big ticket items than you are having a whole lot of lower priced items.

Yeah I don't see the need for money either.

Best items are aquired thru quests, like ballistic weave and Lorenzos serum for example.

Best weapons and armor come from legendary drops.

I feel like once you are over 3k caps, they just keep piling up and before you realize it, you're at 50k+

I was going to take local leader to build up a good source of income, then I was going to use that money to buy up all the junk i need for crafting my equipment as well as all the ammo I could ever desire.

i need it more for ammo, I'm a trigger happy gun player.