Go to the village in the menu, select "Costalots", and buy Chili Seeds. They cost 22 coins each. Purchase as many as you can afford, then go back to your garden. They should automatically plant themselves if you selected it. If not, go around and put them in. Once done select the watering can. Water all of them until the leaf turns blue. Do not over water them or they will die. This works better if you have the golden watering can or the glass can. Attend them until they detach from the stalk. Select them all by using the "Sell" button. Sell them all. They will sell for 100 coins each, giving you a profit of 78 coins. Do this as many times as desired for unlimited money. Note. If you put red fertilizer on them, they will grow and you can sell them for 400 coins, but this is very time consuming.
You can do this with any of your Pinatas. The highest valued ones should work better. Make sure you have at least two of the same kind of Pinata and make sure they can romance. You can have more than one just in case one of the two becomes ill or gets eaten. You must have the correct type of house for them to romance inside. Romance them and let the egg hatch. If needed, let your Pinata hatch out of its cocoon. Do not keep the new Pinata, but instead sell it for the chocolate coins. Continue doing this to get as much money as desired.
Dig holes and put Chili Seeds inside. Then put Red Fertilizer on them four times.
If you need a lot of money in about two days, grow Poison Ivy and sell it. Make a fence about 7x5 near one of the borders of your garden. Buy about five pieces of Poison Ivy. Plant them and wait until they fall apart at the end of their life stage. Sell the flower heads for 100 chocolate coins and the seeds for 20 chocolate coins.
Have several gardens. You only need a few of them to complete this task. You will also need Whirlms, a Whirlm house, and The Shopkeepers store open. Have your Whirlms Romance repeatedly. Collect all the coins in the Romance maze. Also, buy cheap Flower seeds and plant them. When they are done growing, sell all of them. This works best when you have many flowers. While you are doing that, the Whirlms might start Romancing on their own, but be warned; protect the Whirlms. Fudgehogs are very greedy for Whirlm Candy. When you have lots of Whirlms, sell a group of them, but keep at least two. Note: Heavily populated Gardens are a bad place for just two Whirlms. Do this with more than one of your Gardens, you should become rich. Also, Fudgehogs, Sparrowmints, and Serpents are worth a lot more. Breeding them may be slightly more difficult, but they them and their eggs are worth a lot of Chocolate Coins.
Buy a Torch from the Costol Store. Put it in your garden. Go to Gretchen Fetchum and get a Taffly. Do not get it from Express. Once you get it, direct it to the Torch so that it catches fire. When it is on fire, put it out with your watering can and it will turn into a Reddhot. You can now sell it for 2,100 coins. Do this as many times as desired for some extra money.
To get easy money with no spending, select the shovel and hit Seedos as many times as desired. Later he will come back with Weed Seeds. Plant the Poison Ivy Seeds away from Pinatas and keep them growing until they die on their own. The flower heads will be 100 chocolate coins.