Buy needle minder only, scissor keep only, or make it a set (1 needle minder, 1 scissor keep). Scissor keeps are approximately 10cm long or thereabouts not including the clasp.
Scissor keeps are made from a variety of beads and charms including: wooden, resin, natural stone, natural gemstone, hand painted, acrylic, metal, clay, porcelain etc depending on the design. 
Photos are representative of what you receive but there may be slight variations between appearance in those that use natural stone/gem beads/hand painted beads.