I make my own circles from the template plastic which is heat resistant, meaning you can iron over it. Trace the circle the size you want, cut it out--remembering to turn the plastic into the scissors while cutting to get a smooth edge. Then feel the edge of the circle for any tiny bumps or roughness and smooth those with an emery board, and you're good to go! I have a circle template thing with all different sizes of circle holes cut out of it which I often use for tracing. It's available wherever school supplies, etc. are sold. I also will trace around coins or buttons, etc. if they are the size I need. Once you have your plastic circle ready, trace around it on the wrong side of the fabric and cut it out leaving yourself about 3/8 of an inch seam allowance. Stitch a running stitch all around in that seam allowance, and overlap the stitches a bit at the starting point. Put the heat resistant plastic circle against the wrong side of the fabric and use the thread tails to gather up the seam allowance around it like a shower cap. Press it crisp with some spray starch on both sides while the heat resistant plastic is still inside. After it cools, loosen the gathered seam allowance a bit right at the starting point of your running stitches and pull out the template plastic. Now use the thread tails to again pull that gathered seam allowance tight and the applique circle is perfect again and will easily applique down, keeping that perfect shape.