How do you get bells on Animal Crossing ds

You get bells by collecting items, such as shells, fruit, insects, fishes, flowers and much more and selling them to TomNook's shop. Just talk to him and then click 'I want to sell' option. Although TomNook does not except 'Pitfall seeds'.
Another way to get bells is shaking trees. 100bell will sometimes fall out; but watch out for bees!
And one other way to receive bells is by hitting rocks with the shovel. Only one rock in your town will have bell sacks in them. But only one rock a day will bee able to do this.