One of my favorite items to make are jars. They are also one of my favorite items to use. For me they hold lots of possibilities. You can "put things in them", that is useful to me.
These little guys stand under 4" and were made with salt in mind. My daughter asked me to make something for a gift which could hold salt- I came up with these and have been making them ever since.
They will also hold, lose change, jewelery, sugar, and whatever your imagination wants to put in them.
I have made some for the next kiln load, but I really like the little matt yellow one in this picture.......not that I don't like the iron red one as well- we'll it's like your kids- you love them both!