Save some lids from canned goods.
Wash and dry. Hammer down any sharp edges (or use a “no-sharps” opener). Paint them white with latex paint. Let it dry.
Have the students decorate and after the lids dry, use a hammer and nail to make holes for craft wire or ribbon.
Evangelism/Community bonus tip: Have a party, make them and later distribute at your local assisted living or nursing home and sing carols, share the real meaning of Christmas, and spend time with those who may be alone for the holidays.
All the while, you will be building relationships, sharing Christ, and making memories!