We try to keep Christmas on the simpler side every year. Our children get plenty throughout the year. They are allowed to put three items on their list to Santa. This way we know what they really want. And they know Santa will not get anything mommy and daddy don't agree with, so this helps them choose carefully. It's great that my daughter WANTED a kindle last year. But she was not responsible enough for one. We told her she wasn't ready and she thought more carefully about her list. And there was no disappointment Christmas morning.
As for things to make Christmas meaningful and less materialistic...
We like to string popcorn on our tree. Yes it makes a mess while we are doing it. BUt it is very inexpensive. The kids love it. It's a project that takes a few days and they are always so proud and excited of the end result. And after the holidays we put it out for the birds to eat.
We don't exchange gifts with our friends. Instead we go do something holiday oriented. Last year we took the kids to a local mall for a free puppet show. One year we made ornaments together. We have done things that cost some money too, but most get togethers are free or cheap. Our close friends now call to plan something, rather than gift giving.
We do the cookies, lights and gingerbread houses. I think we may "steal" a friend's idea (I did okay it with her). Her daughter makes "gladness jars". She fills mason jars with candy and treats and drops them off at fire departments and police stations. I think she even brought some to the local children's hospital.
We make things for our neighbors, the trash men, teachers and our mail carrier. Last year it was salsa, one year it was chocolate dipped marshmallows. THe kids get the fun of creating and appreciating workers in the community.
Movie nights are always fun. We have a "ban" on anything Christmas until after Thanksgiving.
Many churches in our area do live nativity scenes. We are not religious, but we have done that as a family too. And it costs nothing.
Stories. There are TONS of Christmas books available. ANd they cost nothing at the local library. Now that my son is older, he is often caught reading to his sister.
Last year, we changed up our advent calendar a bit, Instead of candy, I made a simple one with something for us to do as a family each day. It may be watch a movie, make cookies, decorate and ornament or some of the other things mentioned above. Hot cocoa for dessert. Donuts for a breakfast. We also had game nights as an activity. Video game challenges. minute to win it games. It wasn't all necessarily "holiday themed". Just something fun to do together that evening. And it took a little planning. There were days where I had to sneak over and switch things around, because I knew we wouldn't have time for whatever may have been planned that night.
I know as a mom, you worry about disappointment. I imagine your kids will be thrilled Christmas morning!