I loved these magnets when I saw them on tipjunkie! Such a great tute and so easy to make. I don't do much scrap-booking so I don't have much left over paper, but I used anything I had to hand- magazine piccies, origami & letter writing paper, old stamps, even the inside of old envelopes. The cardboard from an old box rather than coffee sleeves. I also painted mine with clear nail varnish as I can't get hold of modpodge.
One tip: wipe your sewing machine needle with an wetwipe afterwards as it does get a bit sticky from stitching through the double sided tape and you don't want it to be all gluey for the next time you sew.
Recycling my trash has never been so fun when it turns into cute hello kitty!!!!