Made a bracelet with matching necklace for the 5 to 7 girls age group. My favorite elastic string for making these is the Stretch Magic brand which I found at Michaels. I used the .7mm. Found the beads new in package at my favorite local thrift shop. I used clear nail polish to cover the overhand knot used to join the pieces.
Also made some hair elastics / bracelets from decorative elastic by Dritz. Was lucky enough to find these 3 colors new at the same thrift shop. I used clear nail polish to seal the edges of the elastic.