It's cheap and easy to make. You will need: cardboard, scissors, pencil, and model magic clay from crayola (you can get it at any craft store).

Step 1: Drawing Out the Shuriken

I start out by drawing a cross so it's easier to draw the points of the star. The size of it only matters to how big you want your shuriken to be. The circle has to be big enough for your finger to fit through.

Step 2: Drawing the Points

Now draw the rough outline of your shuriken. Use the cross lines to make the points of the throwing star. The little lines that stick out of the circle make it easier to find the middle where the two ends meet. Make sure each point is similar in length. I know I am not the best at this, but in the end it will turn out fine.

Step 3: Cut Out the Hole

Now for the fun part. Stab the heck out of the circle so you can make the hole! It doesn't matter how much you get out at this point, because you will be touching it up later. Just be careful on this step not to get your hand in the way of the stabing.

Step 4: Cut Out the Shuriken

The simple part. Just cut the shuriken out of the cardboard. =D

Step 5: Cut the Hole Out, Again

Cut out any of the remainder cardboard thats still hanging from the hole. It should be easier now that the shuriken is cut out. It should now be a nice clean cut hole that you can spin on your fingers.

Step 6: Molding on the Clay

Now take your black Model magic clay and start molding it onto the cardboard cut out. Flatten out the edges to make it look as good as you can. It won't be perfectly flat but it's just for fun . Make sure you can get out as much of the creases as you can. If there are big creases when the clay drys and hardens, they will stretch out and deepen.That will take away from the apperance. So try not to let that happen.

Step 7: Let the Clay Dry and Harden

It should be pretty flimsey and squishy right now.So let it stand out on a table for the night so it hardens. I find that by the second night you have it is at its hardest.

Step 8: Woo, You're Done

Well now you are done. Have fun spinning it around your fingers and throwing it at unsuspecting people! >D
I have made tons of these things, and they variy in size (basically because I don't pay attention when drawing them out). The one all the way to the right is the one I made just now.