Santa as a pen pal
I haven’t tried this, but it sounds good if it delivers good behavior until the holidays!! Visit magical santa letters to personalize a postcard from Santa to your child. You can write as much as you want (as you are the person who KNOWS what will work with your kid!!) and then it ships to your child through the mail. This could be money well spent!
* The earlier you buy a card, the earlier it arrives = better behaved children for a longer period of time.