Currency investment question

I'm looking to invest in certain currencies, specifically the Chinese Yuan (CNY) to start.  I am looking for the most economical way of doing so and noticed banks offering to sell it (most likely for travelers) but are charging a hefty fee in doing so.  Really not interested in paying juice to buy a currency.  I am from San Francisco and have thought about venturing into nearby Chinatown for options, but need a bit more education first.  Anyone have recommendations for a novice such as myself for investing/purchasing and holding Yuan (or other currencies) ?  Do currency Black Markets exist in the US?

buy it on the forex exchange .. Why do you want to buy and keep in a shoe box?? If its worth more today then yesterday then you will make money , if not you will lose money, that simple. This is what forex traders like myself do everyday, we buy money at one price (on the exchange) and sell it for another price. simple.. There are thousands of brokers you can open an account with and buy whatever currency you want.. 

I use FXCM have not had a problem ever... If you read reviews on the intenet all you will see are bad reviews .. I have not had any of those problems. I trade with a PRO account and make a large amount of trades a month. I get a call ever month or so asking if everything is ok.. But research forex before you go jumping in with both feet , money moves very quick, you can be up big one minute and down big the next..I do mosly short term scalps , but if you follow guys in the USD/JPY thread you will profit , there is no doubt in my mind. Those guys know how to trade and  will hold trades for awile and let them run .. Long term is the way to go in forex, you can make some real big gains , but the losses can crush and account as well... 

The Forex isnt really buying a currency, it is buying a currency VS another currency...