How do I sound proof a bedroom door without going broke
You could try attaching cork panels to both sides of the door, but if the door is hollow, you won't have much in the way of insulation to stop sound transmission.
If nothing can be done to the door's interior, you could supplant the cork with quilted fabric, cut to fit the front and reverse of door.
Good info at this site: https://removeandreplace.com/2013/12/13/how-to-soundproof-a-door/
Hope one of those ideas works for you!
Add a thick interlinked drape to inside that you can push open or closed as you need to. Drapery is a great insulater.