First, you'll need a golden shovel. Get it by burying a shovel for 24 hours. If you want a money tree (a tree with 3 30,000 bell bags), you'll also need a four-leaf clover. Put the clovers to get that, but you have to have luck.
So what you do is you plant the four-leaf clover. Behind it, use the golden shovel to bury 100 - 30,000 bells. The more you bury, the higher a chance you have of getting a money tree.
If you're trying to get a normal tree, bury 100 bells and it'll grow into a tree for sure. This saves time when you can't wait for Nook's Cranny or whatever store you have to restock and is great help when you're trying to get the golden watering can (have a perfect town for 16 days).