I have to do 1 or 2 daily roundtrips between the Hong Kong International Airport (HKG) and Hong Kong Kowloon/Central station for one week. Using the normal fare, it is quite expensive: ~110 HKD (~=14 USD) one way (mirror). Is there any weekly pass for the Airport Express in Hong Kong?
According to the MTR website, you only pay 110HKD in total from Hong Kong Station if you return on the same day and use your Octopus card. This seems to be the cheapest option if you want to take the Airport Express.
Otherwise, as B.Liu suggests in the comments, take the Tung Chung Line from Hong Kong Station to Tung Chung (23.6HKD) and then get on a bus like S1, S56, S64, E33, etc. (~3.5HKD) to the airport. In this case, a Tung Chung Line Monthly Pass might make sense for you.