Why was I charged 50 cents?

When linking a debit card with Octopus, a temporary one-time, 50 cent ($0.50) authorization hold will be placed to verify your account, which will be automatically released after 7 days.

Again, this hold is temporary and will be automatically released after 7 days. 

Refer to the image below for more information about this hold, which is displayed when submitting an application with Octopus.