There are several expansion packs for the Sims 2, one of the most popular being Bon Voyage. One of the best features of Bon Voyage is the ability to find and buy jewelry. Your sims may find jewelry hidden around various spots in the game or they may simply buy it. Once obtained, you may wear the jewelry, give it to another sim as a gift or sell it. Your sim may get its hands on special jewelry unique to the area it was obtained.
Send your sim on a vacation.
Purchase jewelry on vacation lots. Check Twikki Beach, Three Lakes Market and the Takemizu Pagoda and Market.
Purchase jewelry in community lots is also possible. Obtain a jewelry display and set it up inside of a store. Once this is done, you will be able to buy and sell jewelry inside the store.