These are the microbeads. I got mine from Michael's and I think they were about $4.00. Mine were in the aisle near stamping supplies. They come in loads of different colors and also in little mini packs with the different colors.
You can see where some of my beads fell off after a long day of work.... Super easy to fix though. Just take a toothpick, dab it with some top coat, dab it on the nail, put the toothpick in the microbeads, and place them where they're needed.