Of course, you can buy cheapo household sponges and cut them into whatever shapes you want, but this can sometimes be a little tricky if you are trying to make more than just the very basic shapes. If you do want to make more detailed shapes, I would suggest giving Miracle Sponges
a try! A Miracle Sponge is a sponge that is thinly compressed to resemble a piece of paper. You can easily draw your design on the 8" x 11" sheet and cut it out. Once water is added the sponge swells to the size of a normal sponge.