Advent calendars are lots of fun to use in December. It gives everyone something fun to wake up to each day.
One of our kids was born on December 1st. Because of that, our Advent calendar was very important. She put the white stuffed cat on her birthday every single year. I made the advent calendar when I was pregnant with her and was on bed rest for a few days.
If you don't have an advent calendar, one inexpensive thing you can do is to wrap up all of your ornaments and have the kids open one a day from December 1st through December 25th.
Try making 25 sugar cookies and wrapping them in bags. Each day of December until Christmas, you get to eat one of the cookies. You can even hang them from your Christmas tree if you want.
Buy an inexpensive chocolate advent calendar and every day you or someone in your family gets the piece of chocolate.
Make small Christmas stockings to put little gifts or candy in each day. They look similar to this, but you can use old fabric or clothes to make them.
There are lots of ideas here that are very easy and inexpensive, if not free, to make.
Find one that works for you!