Southern Star Kids Bicycle Helmets (48-52cm) $0.50 at Kmart
This was posted 11 months 23 days ago, and might be an out-dated deal
I came across this arvo. Pretty sweet deal.
Looks okay for kids just starting to ride. Size is 48-52cm, which is roughly a size down from adult's small —> http://girohelmetsreviews.com/photo/giro_helmet_sizing.jpg Measure your head's circumference at forehead.
P.S. There was still about 8 when I was there (Toowong Qld).