going to Halloween horror nights I am thinking about buying an express pass if do could get in with the alone or you have pay for admission fee AND pass?

It depends on the specific Halloween Horror Nights event and the type of Express Pass you are considering purchasing. Some events may allow you to enter the event with just an Express Pass, while others may require you to purchase a separate admission ticket in addition to the Express Pass.

For example, at Universal Studios Hollywood's Halloween Horror Nights, you can purchase an Express Pass that includes event admission, which allows you to skip the regular lines for all haunted houses, scare zones, and shows. However, if you already have an admission ticket, you can also purchase an Express Pass add-on that allows you to skip the lines without having to purchase a new admission ticket.

To be sure, it's best to check the official website or contact the event organizer directly to confirm whether an Express Pass alone will grant you admission or if you need to purchase an admission ticket separately.