From page 7 of the latest WOOLWORTHS catalogue (for items on sale 24 January 2011): which I received this morning.
FREE gift from WOOLWORTHS: Shop with us on Saturday. 29 January and your primary school aged kid will receive a free mini yoghurt cooler.
I cannot find any T&C's related to this offer, but here is the link to the online catalogue (offer is on Page 7 with a picture of the 'cooler')
http://weeklyspecials.woolworths.com.au/getCatalogue.php?locatorID=4418