Here’s an idea “stolen” from a message board, on how to create inexpensive coasters. You can use larger tiles to make trivets too.
I took ceramin tiles (4×4) and decoupaged photos/prints on them. If you get them from a wholesale supplier, they were cheaper. I am getting them for $0.17 each – so a set of four coasters, basically cost me less than a buck fifty. [ed note: You can get inexpensive tiles from the Rebuilding Center on Mississippi Ave. ]
Anything you can print on your computer, can be placed on a tile coaster. I have done kids photos, snowmen, flowers/verses, local school mascots, etc. Literally anything you can print, you can use for these.
Using Modge-Podge (available at Michael’s and other craft stores), adhered the photo/print to the tile coaster. You have to be careful to use a SMALL amount of M-P because if you don’t, it will bubble. I have found if I use too much M-P, it creates more problems.
I set out like twelve at a time, and by the time I got the 12th one on, I could go back and put a coat on the tops of the first ones. After that first top coat, I waited about 30 more minutes before putting on a second top coat – with M-P. After that dried, I sprayed a coat of acrylic spray sealant. VOILA! A set of four coaster tiles!
Seriously, anything you can print on your computer, can be used. I found it best to use THIN paper. Also, trial and error proved that a smal amount of M-P was best, on the first two coats, 1) adhering it to the tile, and 2) the first top coat) so that the color didn’t run. Once those coats were on, I had no problem with it running/smearing.
It might be worth the price of admission to have your kids draw onto coffee filters with markers and using those drawings 
