Here we go:
VC :
1. guard at gates to inner city can give quest for gathering rent - 800 caps if not finish quest and 400 if complete.
2. 3 merchants in inner city : armor shop: can buy metal armor and spawning about 1.2k caps about each hour or two, gun shop can buy 14mm ammo or sniper rifles, spawning 960 caps, drug shop - about 666 caps, buying stims. (metal armor - raiders or regulators, 14 mm - countryyard shop, sniper rifles - vc patrul, stims - raiders at modoc)
3. look at jerky meat delievery from modoc, guy in bar paying 140 caps for 1 bag + exp.
4. merchants at coutryyard buying : happy harry :ammo and guns, bar :melee weapon and good guns, clinic - drugs ( but not buying healing powder and weak healing powder ).
5. quests for citizens in vc is not giving caps and even no stuff, just exp.
Modoc:
1. balthas often spawning about 400 caps, you can sell to him any armor
2. bg shop, same, about 400 caps often - can buy rockets
3. jerky meat guy shop at entrance, can buy almost all, spawning 240 caps and drugs and holotapes, not sure about brahmin hides, but they are here often.
4. main shop at modoc - 666 caps or about 1k + good guns, can buy combat shotguns, ropes, tobacco.
5. jerky meat delievery to den, vc, ncr, not sure about hub (150 caps each delievery)
Den:
each merchant often have caps:
1.becky : can buy healing powder and alot stuff, she got drugs and caps often
2.armor shop : buying all armor and not sure about healing powder, spawning caps and ma 100/100
3. gun shop nearby becky - buying rockets, spawning good guns and caps
4. other merhcnats buying healing powder (1 more bar and mom's dinner)
5. metzger - not sure.
Clamath:
1. gecko hides at main building - 100 caps for 4 silver and 200 4 golden gecko hides by dialog to cassady's *wife* doughter.
2. bar maybe spawn smthn, but seems lootable and no stuff there to buy.
3. tanker quest : 7k caps in locker, quest you can take at building nearby forest entrance from dirty trapper if you have 2 guys with you.
Box carrying bussiness:
1.ncr train station, 2.hub, 3.boneyard scavengers, 4.sf poor city part. (100 caps each)
Hub:
1. shit shoveling give's here 10 caps per 1 shit
2. water delievery quest - 100 caps (but alot time to spend)
3. at boneyard train station is guy in robe, offering flower - ask him for job
here is easy quest, deliever electronic book to guy in station office - 800 caps.
4. armor shop spawning not often about 1+k and buying metal armor and rockets and some other stuff, other shops spawning some caps + drugs.
5. quest at armor/bg shop - about 500 caps and blueprint, also - more speech/ch - better reward.
6. (edited) : mick in maltese falcon, all quest can give about 800 caps or about 1k, but require alot trawelling, also you can manage to get clj in end of quest.
Boneyard:
1. gr delievery quest - 250 caps if delievery package to sf
2. killing dog quest - no caps but ammo, you can sell ammo to shop here.
3. at scavengers town you can sell junk for 5 caps each by dialog.
4. shop at gun runners spawning 1.8k caps per few hours or about each hour.
Junktown:
1. repair robot- some caps and 223. pistol bp
2. repair power plant - 1, 2, 3k caps , depends on speech and ch. (level 4 req)
3. sell some stuff at main shop, not sure about caps quantiny he spawning.
(can sell here ropes, ammo, guns)
4. spears - 50 and 60 caps at building right from main shop.
SF
1. ant quest - 200 caps +3 stims
2. tanker merchants - buying almost all good stuff ( bar, bg/arm, sg) about 1k+++ caps each spawn
3. main entrance shops - mfc, sec, ew - 1,8 k caps spawn
4. Scorpion quest at SF spawn point (you need die at sf area to enter)
NCR
1. almost no caps at all - look at job for vestin - 100 caps, and some caps for rail gang quest.
2. Shoveling brahmin shit is not bad at ncr, if avoid pkers, 10 caps per 1 shit, also same at hub (10 caps per1)
so if you ll manage to shovel 20 cows you ll get 200 exp and 200 caps. (and better take 50 science at start for get extra exp+100 science for extra sp) look at support perk section for details.
Redding
1. doctor have caps and drugs, you can buy good drugs from him for stims and sell them to players.
Other towns is poor for caps, try them all for quest and check merchants, for hour or 3 is possible to get few k caps or even more than 10k
also selling brahmins, slaves, killing players, killing tribals (they have caps and spears) and all other trading / crafting / bla bla can give some caps.