I have to say that making coasters is one of my favorites things to do because you can use almost anything to create a design. Make sure you do this in a very well ventilated area, because the smell is strong. Here is what you will need:
Clear Casting Resin w/ Catalyst (I purchased mine at Hobby Lobby, it's the best one I have used)
Mold Release Spray
Molds (any shape will work but make sure they are okay to use with resin)
Measuring Cups and Stir Sticks
Your choice of design elements, for these I used scrapbook paper but you can use fake flowers, bottle caps, etc.
I traced the mold onto the scrapbook paper and cut it out.
Clean the molds and then spray with the mold release, let it dry and then repeat. Let it dry completely before starting.
Add approximately 20 drops of the catalyst and mix together
Pour 2 oz of resin into the prepared mold
Add your design element and pour an additional 1 oz of resin over top (if you use bottle caps or flowers they will shift so just use the stir stick to move them back into place)
Repeat the process with the remaining molds. Let them cure overnight before attempting to remove from the molds.
Once completely hardened they will be relatively easy to remove from the molds and they will look like this!