I forgot to give you "the poem" my parents used for stockings, and which we still do....
Something you want
Something you need
Something to eat, and
Something to read
Ea was always a load of fruit each (red apple, green apple, kiwi, banana, orang, satsuma) and a half pound box of sweets. We loved it and used eat fruit all morning with some sweets, but eke those out over the hols. Normally, fruit in our house was boxes of golden delicious apples and not else, so a Granny Smiths AND a red one! as well as other fruit! was great.
Read...always had a book. In fact, anyone on my parents house on Christmas Eve still has to put out stockings for fruit, sweets and a book. Youngest is 29!!!
At that age, you could get the night before Christmas, to read every Christmas Eve afterwards, or there's lots of lovely mr men Christmas books that would be cheap.
Need...things like knickers (character ones are fun as mum wouldn't normally buy those in our house so it must be Santa), hair clips and bobbins, socks, maybe a brush for themselves (always helpful when getting into school etc to reduce passing any nits infestations through whole house by having own brushes), toothbrush, toothpaste, warm vests....all sorts of small but useful things. I think, when dd was that age, I got her a metal kid sized cutlery set in lidl which was very useful and she still uses (small hands). Smaller doc can have sippy cups, bins suited to larger baby feeding herself, also vests etc if need a few extra, first toothbrush.....
And hen, your wants space is drastically reduced to fill out with small things to make it all fun. I love the balloons idea, crayons or pencils always go down well, if you do any crafts or baking or anything together, things for that are nice, either materials/ingredients, or aprons or coveralls.
Keep an eye here and on money saving expert boards for free ideas and free offers, samples sizes etc can be handy.
An m I have posted a list before of lots of ideas for advent calendar things to do, I can,t post it from here now but it was over 60 and lots are free or very cheap. So for a few things to do before Christmas, you might find a few ideas there. Including go for a walk in a woods one day and look at natur sleeping but also collect pine cones, and nanother not so nice day, decorate those with glitter and paint for the tree or grandparent presents. Borrow DVDs from library or Christmassy stories, ton enjoy together on rainy days.