We will focus on standard On-Loan Adult card here. - The most common place to get one is the customer service centre of MTR station (MTR=metro/ subway system in Hong Kong), and the customer service counter of the Airport express. - When you buy one, it will be $150, including $50 dollars as deposit and $100 as credits. - You can refund your Octopus Card when you leave Hong Kong. They will refund the remaining value of the card and the deposit to you, minus a $9 fee if returned less than 90 days after being issued. - You can use it to pay at many shops, like convenience stores, McDonald's etc
- You can use it to pay for ferries and bus. Taxi supporting Octopus Card is very very limited.
- You can recharge credits at shops like 7-11 or MTR stations - When you use it to pay for your transportation when riding MTR, the fee is cheaper than purchasing a single ticket. That's the incentive for many people to get one.