Toys... and fun things....in their many forms,
aren't always bought from a store.
Sometimes it's more fun to be creative and make your own.
Nowadays, there's much more information available in order to
do this as its pretty amazing what you can find
if you just search for it. 
How to make a paper crown
A simple project that can be worn after it's created is a paper crown. These can be done with different colors, themes, and created for a multitude of celebrations, plays, or just for playtime.
Feel free to use different colors that are appropriate to the theme, or even just the child's preferences.
Materials you'll need:
Thin Cardboard of the (usually) non-corrugated or 'shipping box' type.
You can use poster board, old cereal boxes, or some other packaging, if it's large enough.
Foil gift wrap or colored construction paper
Scissors (safety-scissors preferably for the children to assist with cutting)
Paint, crayons, or felt-tip markers and/or pens
Glue and/or tape
A stapler and staples
Optional items could include:
stickers
large markers
glitter
pre-cut shapes or shapes cut from other cardboard packaging
Instructions:
Cut a strip of cardboard approximately 3-4 inches wide, and long enough to go around the head and overlap slightly (about 1/2-inch). If your piece isn't long enough, you may have to tape or staple two pieces together end-to-end.
Next, cut a piece of the colored construction paper or foil gift wrap, but make it slightly wider (about 2" or more wider) and again, you may have to staple or tape two pieces together to make it long enough.
Now, glue the construction paper to the cardboard so that the bottom edge lines up.
Cut a zigzag (or other pattern, if you really feel fancy) along the top edge of the construction paper.
Please note: one reason it's a good idea to have the construction paper wider is that it's difficult for some children to cut the zigzag (or other pattern) edge along the cardboard. With the wider construction paper, it seems to be easier for them to accomplish this task.
Then, decorate the paper side (not the cardboard side) with your markers, glitter, stickers, or all-of-the-above.
Now that the decoration is completed, it's time to connect the ends and make a "ring" (adult assistance may be needed for this step).
With the cardboard on the inside (towards the head) of the ring and the decorations on the outside, you will want to bring the ends of the cardboard together with either staple or tape.
Once it's together, you're finished!
Enjoy your new creation! 
IF... you dont have the time, maybe you can find
a Couronne en Papier (paper crown) somewhere nearby.