You can do both!
For starters, check your pockets, purse or wallet, desk drawers, and under the sofa cushions.
You'll be surprised at the coins hidden in the nooks and crannies of your home.
Then, ask friends and relatives if they have any old or unusual coins to contribute.
When it comes to buying coins, there are several options.
You can purchase rolls from the bank to look for more common coins.
Or you can buy new issues directly from the United States Mint.
For older coins, visit local coin shows with your parent or a guardian.