When charging your card, our payment gateway sends a request to your bank for either a $0 or a $1 authorisation (different banks permit different amounts) to verify that the card is issued and the bank will allow it to be authorised. This authorisation request is then immediately reversed. However, you may still see an authorisation for $1 on your credit card statement. The important thing to remember is that this is not a charge, and it will disappear from your statement; depending on the bank, it will be removed from your statement in anywhere from a few minutes to a few weeks.
You can also confirm this process by contacting your bank or financial institution directly.