Hong Kong Currency

Currency
The legal tender is the Hong Kong dollar (HK$), which is linked to the US dollar at a rate of about 7.80 HKD to 1 USD, although exchange rates may fluctuate slightly. Interestingly, Hong Kong banknotes are issued by three banks (HSBC, Standard Chartered Bank and Bank of China), and vary in design and color for each denomination.
Banknotes
$10 - green or purple (The purple note is issued by the government)
$20 - dark blue or light blue (old or new)
$50 - purple or green (old or new)
$100 - red
$500 - brown
$1000 - yellow
Coins
10c - in bronze, circular, smaller
20c - in bronze, wavy-circular
50c - in bronze, circular, larger
$1 - in silver, circular, thinner
$2 - in silver, wavy-circular
$5 - in silver, circular, thicker
$10 - in bronze/silver, circular
Octopus Card
The Octopus card is a stored value electronic card widely used in Hong Kong for public transport, purchases in convenience stores, fast food shops, supermarkets, cake shops and vending machines, etc. You simply place the Octopus card over a reader, and the correct amount is deducted automatically from the stored value. With an Octopus card, you no longer need coins. Money Exchange
You can exchange your currency for Hong Kong dollars at authorized money exchangers. At Hong Kong International Airport, currency exchange counters are conveniently open from early morning to late at night. There are 24-hour automated teller machines. The exchange rate fluctuates daily depending on the money market.
ATM
Automated teller machines (ATMs) can be found almost everywhere and some HSBC 'Electronic Money' machines provide 24-hour cash withdrawal (HK$) facilities for Visa and MasterCard holders. American Express cardholders have access to 'Aeon' ATMs and can withdraw local currency with Express Cash service in town
Traveller's cheques & Credit Cards
Traveller's cheques are accepted by leading banks and hotels.

International credit cards such as American Express, VISA, Diners Club and MasterCard are also widely acceptable at hotels, retail shops and restaurants. Such premises usually display stickers of accepted cards at their entrance.