Coasters are so expensive to buy and hard to find in the colors you'd like. Here's a clever way to make them without having to make binding.
For Christmas 2016, I made these coasters using the video below. To make one coaster, I used six squares of fabric, each one a 5 inch square plus one 5 inch square of batting. For one of the squares, I used a polyester twill fabric (which is more dense than the other cotton fabrics) Place the twill fabric on top of the batting and then a cotton fabric square under that. Now you have 4 squares left and you need to fold them in half across the diagonal and iron the fold. Then place them according to the video. Sew around the edge and turn inside out. I then sewed across the diagonals so the fabrics wouldn't open up too much.