Stanley Gibbons website is an online location to buy and sell rare coins. It also has brick-and-mortar locations for customers. Coinstudy.com is another website that lists values of rare coins. Heritage Auctions provides a basic price guide for U.S. currency.
Stanley Gibbons also buys and sells rare stamps and postcards. Coinstudy.com does not have store locations but is easily navigated. Heritage Auctions sells many different products, not only rare coins, but is a good source for estimating selling prices for all U.S. currency from the 1800s forward, including Confederate money. Heritage Auctions also helps sellers find what coin they are selling.