You can find inexpensive packages of red, green or Christmas decorated baby and toddler socks and/or booties on sale now. Purchase a couple of packages and just sew a loop at the top of them to hang on your Christmas tree or you can just use standard ornament hangers.
These are lot less expensive than standard pre-made stocking tree decorations and would be especially nice if you or someone you know has a newborn or toddler to be able to reuse for the wee ones to wear on or after Christmas Day or simply save for next years decorating ;-)
Source: Just thinking about how expensive Christmas tree ornaments are and thinking of less expensive solutions.