The Shay Coaster is an easy crochet project worked in simple single crochet stitches. You can also use this little square as a mini washcloth too. You'll need just a small amount of worsted weight cotton yarn per coaster, making this a great stashbusting/scrap yarn project. I used WeCrochet Dishie Yarn for mine. If you are only making a coaster that will house a cold or hot beverage, you can use acrylic yarn (like Red Heart Super Saver) as an alternative with an I9/5.5mm hook - just do not put anything fresh from the oven on the acrylic coaster, or you will melt the fibers and risk burning yourself. I was able to work up one coaster in just under 20 minutes.
