How much does it cost on a regular day basis ?

It depends on what day of the week, if it's a matinee or not, if it's a special event, if it's "d box" seating, etc. Their website has all the information.

Prices vary depending on format and time to you go. Check out prices for the movie and time you want to go at: https://www.cinemark.com/central-california/century-14-northridge-mall