I think monster doors are so cute and fun for kids. My birthday is at the end of September. I recycled the streamers used at my party and made a monster door.
Since I already had the crepe paper, all I needed was 2 paper plates and a black piece of card stock. Just trace two circles on the card stock and tape them to the white paper plates. Then just look at your favorite monster on Pinterest and copy it. I didn't have clear tape so you can see the tape a bit. I also taped down the last couple streamers on each side so they wouldn't get caught in the door.
Here are some other monster doors from Pinterest.
My kids think our door is awesome and the trick-or-treaters will love it.