Here's what you'll need:
1. Tiles ( you can get these at home depot for 16 cents a tile!)
2. Modge Podge
3. A paint brush
4. Magazines for cut-outs
5. A can of clear sealing spray paint. ( I found one at Wal-Mart. It says for decoupage on the back)
6. Friends to make them with!
First, decide what you want on your coaster. Then spread a layer of modge podge over the coaster with your paint brush and place your image on top. Then, spread another layer of modge podge over your image to seal it in. Let it dry. When they are all dry, spray a layer of clear sealing spray on top...and wala!
Here's how mine turned out. I wish I would have taken a picture of everybody's because they were all so neat.
Hope you get to make some soon! They're lots of fun!