I know how it is. You've got a house to expand, public works to develop, stuff to buy—whatever your reason, you need bells, and you need bells bad. No worries. I'm here to help you make bank in New Leaf.
When you start out—before you have the island unlocked—the best you can do is to rely on old-school methods. You'll want to make sure you bang every rock you come across with a shovel, because there's a daily money-spawning rock and a gemstone rock—as I mentioned in my original tips article. Sometimes you might even get a rock that spawns multiple gemstones instead of multiple bags of money, which is great. And, naturally, you'll want to search for fossils—these can fetch some decent bells, too.
In addition to that, any fruit that's not native to your town will sell for 500 bells each at Re-Tail, meaning that every tree of non-native fruit nets you 1.5k bells each. It's dependable (non-perfect fruit regrows every few days), and you don't really have to do anything after the initial fruit acquisition and planting. Not bad. If you manage to get a "perfect fruit," you can sell these for 1,000 each—but the trees have a very limited harvest.
Then, of course, there's basic fishing and bug hunting. It's in your best interest to get acquainted with the prices that stuff sells for—the easiest way to do that is to simply look it up. The Animal Crossing Wikia is a good resource for that; eventually you'll start remembering the stuff that's worth good money and the stuff that's not. You'll probably want to avoid stuff like sea bass, horse mackerel and the common butterfly—heck, if you're meticulous, you might want to avoid catching anything that's under 500-1,000 bells. It takes up valuable space in your inventory that can be taken up by something else!
Note that you can make fishing easier on yourself by unlocking the silver and gold fishing rods—these rods attract fish better than the standard one does. The silver fishing rod is available for sale at the museum gift shop, which is a public works project that you can eventually unlock.
If you're willing to take a chance, there's always the stalk market—Joan, a boar, appears in your town every Sunday morning to sell turnips. They're not cheap, but you can resell them at Re-Tail; the resell price fluctuates every day—which means you could get lucky and get a lot of money back if the price gets high enough. If you do go this route, make sure to visit your friend's towns and see what the turnip prices are there, too. Some people like to mess around with turnips, but I personally don't like to have to wait for a return, or that I have to make an investment.
And that's why I think the next method is the best method: beetle hunting at the island. Beetles, on the whole, give you a fantastic return. The only thing you need is 1,000 bells, which is the price of transportation to the island. That's easy to make back, it usually only takes one beetle. You'll want to head over to the island at night, which is when the beetles like to come out and play.
To give you an idea of how many bells we're talking about, here are some prices:
- Scarab beetle: 6,000 bells
- Dynastid beetle: 1,350 bells
- Miyama stag beetle: 1,000 bells
- Saw stag beetle: 2,000 bells
- Giant stag beetle: 10,000 beetles
- Rainbow stag beetle: 10,000 bells
- Goliath beetle: 6,000 bells
- Atlas beetle: 8,000 bells
- Golden stag beetle: 12,000 bells
- Hercules beetle: 11,250 bells
- Cyclommatus beetle: 8,000 bells
- Elephant beetle: 8,000
I said you were going to make bank, didn't I? Yeah. Imagine an inventory full of these babies—you can take 40 items back with you. Anyway, these beetles like to spawn on tree trunks or palm trees—you'll want to shoo out any lesser bugs, like roaches, fruit beetles and the like so that something better can spawn. You might also notice that the beetles are huffy and will fly away if you shuffle too much from far away, so you'll want to get into the habit of walking on the island. Once again, this game hates running!
Additionally, you'll want to make sure you approach beetles carefully; if you hold the A button down while holding a net, you'll go into the closest thing the game has to sneak mode. You'll hold the net up and approach stuff cautiously, which makes it easier to get close to bugs and line your net up.
Stuff spawns rather quickly on the island, but you'll still want to walk around the entire island to make sure new stuff appears. This'll also give you a chance to check if there are any sharks in the water—these also net you lots of bells (so do moths, lantern flys, and generally, big butterflies.) If stuff seems to slow down and few beetles appear, you might want to head back inside the building on the island, and then come back out—it'll respawn everything.
If you're meticulous, you'll want to make sure that what you bring back with you is all high-priced. I don't have the patience for that, and tend to come back with a load that's worth about 150,000 bells after about 15 minutes of work. If you're willing to put in the time and effort, weeding out anything that's not expensive, you can easily come back with a load that's worth up to 400,000 bells. You might want to set the town ordinance to "Bell boom," which will give you 20% more bells on anything you sell, in order to ensure you'll get a lot of money for your efforts. You'll want to sell at Re-Tail, too, not the Nook's shop—Re-Tail tends to give you more bells.
Keeping all this stuff in mind, you should be able to make lots of bells easily. Just don't get carried away—stuff is less fun when it starts to feel like a chore!
Now get out there and make some bells.