I received a separate $1 (or $0) charge on my card after I purchased a Bartleby subscription. What is this charge?

Like many services, we place a pre-authorization amount on your card just to make sure it is valid. This amount is usually $1 but could also be $0, depending on the type of card used. No need to worry – you will not actually be charged anything and this pre-authorization will disappear from your statement after a few days.