Shell

A shell is a common item that washes up on the ocean shoreline in all games. They provide an easy, yet minimal, source of income, and are often used in the first few days in order to obtain enough Bells to buy tools. In, scallops and pearl oysters are deep sea creatures, and are thus obtained from diving, as opposed to shells in earlier installations of the Animal Crossing series. Also, the giant clam-shell can be taken to Cyrus at Re-Tail along with a K.K. Slider song in order to create a music box.

A limited number of shells appear at a time, usually 15. If they are picked up, they will slowly start to reappear. Entering buildings and saving the game will likely cause new shells to show up. Coconuts that wash up on the beach in and  do not count towards the 15 shell limit.

Shell prices and game availability
Prices and availability of shells are the same in Wild World and City Folk.

In Wild World
Scallops can be traded in the golden axe trading event to obtain the golden axe or Pascal's pic. They can be obtained from Tortimer in exchange for a massage chair.

In City Folk
Scallops can be traded with Pascal for an item from the Pirate Theme, including the Sea View wallpaper and Ship Deck flooring. Pascal will only accept the scallop, not the white scallop.