What are good/efficient ways of getting/grinding money in each World?

[Queenofdragons6]

Assume access to previous Worlds, but not subsequent. (I.e., for World 1, don't suggest something that requires a resource or mechanic found in World 2, 3, or 4; for World 2, you can suggest something that requires resources in World 1, but not anything in World 3 or 4; etc.)

[AlphaNexus]

Currently w4 is your best bet to get money (you don't really need that much money before w4) - starting with cooking and upgrading your meals will give you a) +stats (%money, %dmg, etc) and b) access to new special talents which will boost your money gain.

Just pushing to the later maps (w4) with your chars will also net you a good amount of multiple void coins/h because of all those upgrades.

W4 colosseum is probably the best way to earn money (if you need it - I would recommend to keep your tickets for later use).
Either start with a dmg/acc or a drop rate card setup, make sure to have your dr setup equipped and kill the w4 miniboss for eggs/ladles (you'll get more eggs/ladles if you reach certain dr breakpoints), now after killing the miniboss swap to your money/dr/dmg card setup and destroy the chests. Chests can be overkilled -> dmg might be better than a low lvl money card.
You can double the first and last card with chips in the lab - but it's currently almost impossible to obtain them without using the gem shop and even then it's rng whether you get them or some other chips.
Depending on your meals and overall dmg it's not that difficult to get a couple of void coins per run (at the beginning/not that much progress in w4/cooking/lab).
The only limit to how much you earn per run is how many tickets you have -> think about what you currently need / keep the tickets for later once you boosted your money/dr.

The amount of green mushrooms killed (lab bonus will increase money earned by x% per 1m killed green mushrooms) + cooking meals and upgrading them can later easily give you up to multiple lustre coins per run.

[Salmon Snake]

He is months away from world 4 so dont know how much this world 4 info will help him, based on his needs he just started the game.

World 1 I suggest you sell things you craft for free in the anvil, its good money for early game and will give you enough for anything you need. I suggest you find an actrive guild for the guild buffs, they will help you a ton.

[kone]

W1: Cards (Nutto, Baba Yaga) Equips (Goo Galoshes, Double Goopi) Keychains (Piggy Chain)
Dungeon Flurbo Monster Cash Passive and Journeyman Money Talents - farm anywhere at the big tree or sewer - you can also make decent starting cash by selling materials from the anvil, forge or mob drops
W2: Cards (Bandit Bob) Obols (Money, Pop) Alchemy Vial (Bean Slices) Arcade (Cash Bonus Passive) Post Office Box (Utilitarian Capsule) and at this point you should be Crystal Farming as Maestro for extra money - best mob is Snelbies maybe, but push to W3
W3: Cards (Dilapidated Slush) Equips (Honker Hat) - best mob is Rams
W4: Cards (Purp Mushroom) Alchemy Bubbles (Purple, Green, Orange XIII) Lab (Fungi Finger Pocketer, Emerald Rhombol) Lab Chips (Double First/Last Cards, Double Keychain) Meal (Salad, Bunt Cake) Pet Arena Bonuses and VIP Star Talents (Coins for Charon, American Tipper) - push as far as you can while upgrading money bonuses in W4 - the colosseum here and its money output is so potent that if you play on mobile the cash earned here will overflow and you'll get nothing from the chests

Combine everything here as you push farther. The most important, bordering broken bonus is Fungi Finger Pocketer and its jewel. Next is cards and whether you can double them through W4 lab chips, whether it be for AFK, Active Money or Crystal Chance depending on your setup. Obols and the VIP Star Talents are equally strong as third.

Extra money sources you can get anytime are Guilds (Coin Supercharger) and previously the Beach Bro Trophy and an event Card (Meaning of Giftmas)

When entering W4 there might be a couple extra mechanics to keep track of like your STR/AGI/WIS stats for Alchemy Bubbles XIII or whether you can go wild on crystals if you have Chocolate Chip. The lab bonuses Certified Stamp Book, Spelunker Obol and My 1st Chemistry Set also have a slight effect on money through raising stats/jewels/vials.

Lastly, if all you ever want is money then push to W4. Everything before, especially W2 doesn't really give enough or is necessarily strapped for it. It's so much faster and efficient to AFK or Crystal Farm here for money once W4 is unlocked, and the colosseum is insane.