How do you get a money tree on Animal Crossing City Folk?

You must have the golden shovel to plant a money tree. To get it, bury a shovel for 1 day and then dig it up; it will be golden. Cut down a tree using an axe, dig up the stump using the golden shovel, (this gives the tree a better chance of growing) then bury some bells in the hole (1000 minimum) and cover it over with your golden shovel. The more bells you put in, the greater the chance a money tree will grow. It takes four days to bear "fruit" from the time it's planted, and will only do so once. It grows three bags of the amount you buried, and from then on is a normal tree.

First you need a golden shovel. Next you need a bag of bells. If you bury a bag of bells in a hole with a golden shovel, a sprout will come up. Just wait a few days for it to grow.