Bells can be divided by 100 bell coins, 1,000 bell bags, and 10,000 bell bags. 10 of the 100 bell coins placed together will form a single 1000 bell bag. Only 99,999 bells can be held in your Wallet at one time. If you get more than 99,999 bells, Tom Nook will place extra money in a bag of 99,000 bells which will take up one inventory slot. The rest of the money is kept in your wallet. Bell bags are usually only used as payment to other players, or to carry more money than can't be kept in the Wallet. Bells can also be stored at the Post Office in Animal Crossing and at the Town Hall in Animal Crossing: Wild World. After reaching a certain amount of bells you will receive a letter with an item attached.