Looking for a full-face kids bicycle helmet for less than $100. Preferably with the chin-guard being removable.
Catch.com.au have them in the $200-500 range. Wish.com have them for as low as $31 but I'd presume they are not Australian Standards compliant.
Is sub-$100 unrealistic?
For a bicycle helmet I think it will be difficult. You could try a dirtbike helmet as they seem to be cheaper. But heavier. The bicycle helmet are lightweight hence the additional cost.