When my kids were small, we made coasters for Grandparents' Day. I've wanted a set ever since, and so this year I decided to make them for myself for Mother's Day. These are very inexpensive to make and take only a few minutes, but they are very durable.
I bought a set of small tiles from the tile aisle at a Lowe's Home Improvement Store.
Next, I painted my son's hand with simple acrylic paint and he stamped it onto the tile.
We repeated the same step with the other hand on another tile.
My daughter then used her fingers and thumbs to create a flower (her hands are now too big to fit all on one tile).
Next, we sprayed each tile with a clear, triple-thick sealant and allowed it to dry for a few hours. This puts a glossy sheen on each tile and prevents it from being scratched or damaged. Until this point, you can wipe the paint off and start again; after this, your picture is permanent!
Then, I cut a piece of felt a bit smaller than the tile so that it would not be seen from above. This will prevent the tile from scratching any surface on which it's placed. You can also use the sticky felt dots that you can buy, but one piece of felt costs much less than those dots!
Voila! A set of personalized coasters for about less than $2!