These were so fun to make for my third grader! We found these fun 3D stickers at the dollar store for 16 a pack and only had to spend $2 on his valentine cards. My nine year old just loves the heart shaped planets and that I personalized his with his name.
These are great if you want to use other items instead of space stickers as well. Try marbles, bouncy balls, pop rocks, or even glow sticks.
Just right click and save for printing.